diff -rcN Postgresql-CVS-20090313.org/src/backend/access/gin/ginxlog.c Postgresql-CVS-20090313/src/backend/access/gin/ginxlog.c *** Postgresql-CVS-20090313.org/src/backend/access/gin/ginxlog.c 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/gin/ginxlog.c 2009-03-13 16:37:09.000000000 +0900 *************** *** 14,19 **** --- 14,20 ---- #include "postgres.h" #include "access/gin.h" + #include "access/xlog.h" #include "access/xlogutils.h" #include "storage/bufmgr.h" #include "utils/memutils.h" *************** *** 521,526 **** --- 522,631 ---- } } + /* + * gin_readahead - enqueue information about data pages + * + * The readahead module stores information about pages that are modified through + * redo-ing record. + * + */ + bool + gin_readahead(XLogRecPtr lsn, XLogRecord *record) + { + uint8 info = record->xl_info & ~XLR_INFO_MASK; + + Assert(record); + + switch (info) + { + case XLOG_GIN_CREATE_INDEX: + { + RelFileNode *node = (RelFileNode *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(*node, GIN_ROOT_BLKNO, lsn.xrecoff, false); + break; + } + case XLOG_GIN_CREATE_PTREE: + { + ginxlogCreatePostingTree *data = + (ginxlogCreatePostingTree *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(data->node, data->blkno, lsn.xrecoff, false); + break; + } + case XLOG_GIN_INSERT: + { + ginxlogInsert *data = (ginxlogInsert *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(data->node, data->blkno, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + break; + } + case XLOG_GIN_SPLIT: + { + int readahead_cnt; + ginxlogSplit *data = (ginxlogSplit *) XLogRecGetData(record); + + readahead_cnt = 2; + if (data->isRootSplit) + readahead_cnt++; + + if (!ReadAheadHasRoom(readahead_cnt)) + return false; + + ReadAheadAddEntry(data->node, data->lblkno, lsn.xrecoff, false); + ReadAheadAddEntry(data->node, data->rblkno, lsn.xrecoff, false); + if (data->isRootSplit) + { + ReadAheadAddEntry(data->node, data->rootBlkno, + lsn.xrecoff, false); + } + break; + } + case XLOG_GIN_VACUUM_PAGE: + { + ginxlogVacuumPage *data = + (ginxlogVacuumPage *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(data->node, data->blkno, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + break; + } + case XLOG_GIN_DELETE_PAGE: + { + int readahead_cnt; + ginxlogDeletePage *data = + (ginxlogDeletePage *) XLogRecGetData(record); + readahead_cnt = 2; + if (data->leftBlkno != InvalidBlockNumber) + readahead_cnt++; + + if (!ReadAheadHasRoom(2)) + return false; + ReadAheadAddEntry(data->node, data->blkno, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + ReadAheadAddEntry(data->node, data->parentBlkno, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_2); + if (data->leftBlkno != InvalidBlockNumber) + { + ReadAheadAddEntry(data->node, data->leftBlkno, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_3); + } + break; + } + } + + return true; + } + void gin_xlog_startup(void) { diff -rcN Postgresql-CVS-20090313.org/src/backend/access/gist/gistxlog.c Postgresql-CVS-20090313/src/backend/access/gist/gistxlog.c *** Postgresql-CVS-20090313.org/src/backend/access/gist/gistxlog.c 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/gist/gistxlog.c 2009-03-13 16:37:09.000000000 +0900 *************** *** 14,19 **** --- 14,20 ---- #include "postgres.h" #include "access/gist_private.h" + #include "access/xlog.h" #include "access/xlogutils.h" #include "miscadmin.h" #include "storage/bufmgr.h" *************** *** 501,506 **** --- 502,585 ---- } } + /* + * gist_readahead - enqueue information about data pages + * + * The readahead module stores information about pages that are modified through + * redo-ing record. + * + */ + bool + gist_readahead(XLogRecPtr lsn, XLogRecord *record) + { + uint8 info = record->xl_info & ~XLR_INFO_MASK; + + Assert(record); + + switch (info) + { + case XLOG_GIST_PAGE_UPDATE: + case XLOG_GIST_NEW_ROOT: + { + PageUpdateRecord xlrec; + + decodePageUpdateRecord(&xlrec, record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(xlrec.data->node, xlrec.data->blkno, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + break; + } + case XLOG_GIST_PAGE_SPLIT: + { + int i; + + PageSplitRecord rec; + decodePageSplitRecord(&rec, record); + + if (!ReadAheadHasRoom(rec.data->npage)) + return false; + for (i = 0; i < rec.data->npage; i++) + { + ReadAheadAddEntry(rec.data->node, rec.page[i].header->blkno, + lsn.xrecoff, false); + } + break; + } + case XLOG_GIST_INSERT_COMPLETE: + { + /* + * This WAL record never touch data page, so nothi ng + * to do. + */ + break; + } + case XLOG_GIST_CREATE_INDEX: + { + RelFileNode *node = (RelFileNode *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(*node, GIST_ROOT_BLKNO, lsn.xrecoff, false); + break; + } + case XLOG_GIST_PAGE_DELETE: + { + gistxlogPageDelete *xldata = + (gistxlogPageDelete *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(xldata->node, xldata->blkno, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + break; + } + } + + return true; + } + IndexTuple gist_form_invalid_tuple(BlockNumber blkno) { diff -rcN Postgresql-CVS-20090313.org/src/backend/access/heap/heapam.c Postgresql-CVS-20090313/src/backend/access/heap/heapam.c *** Postgresql-CVS-20090313.org/src/backend/access/heap/heapam.c 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/heap/heapam.c 2009-03-13 16:37:09.000000000 +0900 *************** *** 49,54 **** --- 49,55 ---- #include "access/valid.h" #include "access/visibilitymap.h" #include "access/xact.h" + #include "access/xlog.h" #include "access/xlogutils.h" #include "catalog/catalog.h" #include "catalog/namespace.h" *************** *** 4975,4980 **** --- 4976,5127 ---- } /* + * heap_readahead - enqueue information about data pages + * + * The readahead module stores information about pages that are modified through + * redo-ing record. + * + */ + bool + heap_readahead(XLogRecPtr lsn, XLogRecord *record) + { + uint8 info = record->xl_info & ~XLR_INFO_MASK; + + Assert(record); + + switch (info & XLOG_HEAP_OPMASK) + { + case XLOG_HEAP_INSERT: + { + xl_heap_insert *xlrec = + (xl_heap_insert *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(xlrec->target.node, + ItemPointerGetBlockNumber(&xlrec->target.tid), + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + break; + } + case XLOG_HEAP_DELETE: + { + xl_heap_delete *xlrec = + (xl_heap_delete *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(xlrec->target.node, + ItemPointerGetBlockNumber(&xlrec->target.tid), + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + break; + } + case XLOG_HEAP_UPDATE: + case XLOG_HEAP_MOVE: + case XLOG_HEAP_HOT_UPDATE: + { + bool samepage; + xl_heap_update *xlrec = + (xl_heap_update *) XLogRecGetData(record); + + samepage = ItemPointerGetBlockNumber(&xlrec->newtid) == + ItemPointerGetBlockNumber(&xlrec->target.tid); + + if (!ReadAheadHasRoom(1 + (samepage ? 0 : 1))) + return false; + /* store page which contains updated tuple. */ + ReadAheadAddEntry(xlrec->target.node, + ItemPointerGetBlockNumber(&xlrec->target.tid), + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + /* store another page if any. */ + if (!samepage) + ReadAheadAddEntry(xlrec->target.node, + ItemPointerGetBlockNumber(&xlrec->newtid), + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_2); + break; + } + case XLOG_HEAP_NEWPAGE: + { + xl_heap_newpage *xlrec = + (xl_heap_newpage *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(xlrec->node, xlrec->blkno, + lsn.xrecoff, false); + break; + } + case XLOG_HEAP_LOCK: + { + xl_heap_lock *xlrec = + (xl_heap_lock *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(xlrec->target.node, + ItemPointerGetBlockNumber(&xlrec->target.tid), + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + break; + } + case XLOG_HEAP_INPLACE: + { + xl_heap_inplace *xlrec = + (xl_heap_inplace *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(xlrec->target.node, + ItemPointerGetBlockNumber(&xlrec->target.tid), + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + break; + } + } + + return true; + } + + /* + * heap2_readahead - enqueue information about data pages + * + * The readahead module stores information about pages that are modified through + * redo-ing record. + * + */ + bool + heap2_readahead(XLogRecPtr lsn, XLogRecord *record) + { + Assert(record); + + switch (record->xl_info) + { + case XLOG_HEAP2_FREEZE: + { + xl_heap_freeze *xlrec = + (xl_heap_freeze *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(xlrec->node, xlrec->block, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + break; + } + case XLOG_HEAP2_CLEAN: + case XLOG_HEAP2_CLEAN_MOVE: + { + xl_heap_clean *xlrec = + (xl_heap_clean *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(xlrec->node, xlrec->block, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + break; + } + } + + return true; + } + + /* * heap_sync - sync a heap, for use when no WAL has been written * * This forces the heap contents (including TOAST heap if any) down to disk. diff -rcN Postgresql-CVS-20090313.org/src/backend/access/nbtree/nbtxlog.c Postgresql-CVS-20090313/src/backend/access/nbtree/nbtxlog.c *** Postgresql-CVS-20090313.org/src/backend/access/nbtree/nbtxlog.c 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/nbtree/nbtxlog.c 2009-03-13 16:37:09.000000000 +0900 *************** *** 16,21 **** --- 16,22 ---- #include "access/nbtree.h" #include "access/transam.h" + #include "access/xlog.h" #include "storage/bufmgr.h" /* *************** *** 880,885 **** --- 881,1016 ---- } } + /* + * btree_readahead - enqueue information about data pages + * + */ + bool + btree_readahead(XLogRecPtr lsn, XLogRecord *record) + { + uint8 info = record->xl_info & ~XLR_INFO_MASK; + + Assert(record); + + switch (info) + { + case XLOG_BTREE_INSERT_LEAF: + case XLOG_BTREE_INSERT_UPPER: + case XLOG_BTREE_INSERT_META: + { + int readahead_cnt; + xl_btree_insert *xlrec = + (xl_btree_insert *) XLogRecGetData(record); + + readahead_cnt = 1; + if (info == XLOG_BTREE_INSERT_META) + readahead_cnt++; + + if (!ReadAheadHasRoom(readahead_cnt)) + return false; + ReadAheadAddEntry(xlrec->target.node, + BlockIdGetBlockNumber(&xlrec->target.tid.ip_blkid), + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + if (info == XLOG_BTREE_INSERT_META) + { + ReadAheadAddEntry(xlrec->target.node, + BTREE_METAPAGE, lsn.xrecoff, false); + } + break; + } + case XLOG_BTREE_SPLIT_L: + case XLOG_BTREE_SPLIT_L_ROOT: + case XLOG_BTREE_SPLIT_R: + case XLOG_BTREE_SPLIT_R_ROOT: + { + int readahead_cnt; + xl_btree_split *xlrec = + (xl_btree_split *) XLogRecGetData(record); + + readahead_cnt = 2; + if (xlrec->rnext != P_NONE) + readahead_cnt++; + + if (!ReadAheadHasRoom(readahead_cnt)) + return false; + + ReadAheadAddEntry(xlrec->node, xlrec->rightsib, + lsn.xrecoff, false); + ReadAheadAddEntry(xlrec->node, xlrec->leftsib, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + if (xlrec->rnext != P_NONE) + { + ReadAheadAddEntry(xlrec->node, xlrec->rnext, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_2); + } + break; + } + case XLOG_BTREE_DELETE: + { + xl_btree_delete *xlrec = + (xl_btree_delete *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(xlrec->node, xlrec->block, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + break; + } + case XLOG_BTREE_DELETE_PAGE: + case XLOG_BTREE_DELETE_PAGE_META: + case XLOG_BTREE_DELETE_PAGE_HALF: + { + int readahead_cnt; + xl_btree_delete_page *xlrec = + (xl_btree_delete_page *) XLogRecGetData(record); + + readahead_cnt = 3; + if (info == XLOG_BTREE_DELETE_PAGE_META) + readahead_cnt++; + if (xlrec->leftblk != P_NONE) + readahead_cnt++; + + /* parent page */ + ReadAheadAddEntry(xlrec->target.node, + ItemPointerGetBlockNumber(&(xlrec->target.tid)), + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_1); + /* rightsib page */ + ReadAheadAddEntry(xlrec->target.node, xlrec->rightblk, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_2); + /* leftsib page, if exists */ + if (xlrec->leftblk != P_NONE) + { + ReadAheadAddEntry(xlrec->target.node, xlrec->leftblk, + lsn.xrecoff, record->xl_info & XLR_BKP_BLOCK_3); + } + /* target page */ + ReadAheadAddEntry(xlrec->target.node, + xlrec->deadblk, lsn.xrecoff, false); + /* metapage, if exists */ + if (info == XLOG_BTREE_DELETE_PAGE_META) + { + ReadAheadAddEntry(xlrec->target.node, + BTREE_METAPAGE, lsn.xrecoff, false); + } + break; + } + case XLOG_BTREE_NEWROOT: + { + xl_btree_newroot *xlrec = + (xl_btree_newroot *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + /* FPW does not exists. */ + ReadAheadAddEntry(xlrec->node, xlrec->rootblk, + lsn.xrecoff, false); + break; + } + } + + return true; + } + void btree_xlog_startup(void) { diff -rcN Postgresql-CVS-20090313.org/src/backend/access/transam/Makefile Postgresql-CVS-20090313/src/backend/access/transam/Makefile *** Postgresql-CVS-20090313.org/src/backend/access/transam/Makefile 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/transam/Makefile 2009-03-13 16:37:09.000000000 +0900 *************** *** 12,18 **** top_builddir = ../../../.. include $(top_builddir)/src/Makefile.global ! OBJS = clog.o transam.o varsup.o xact.o xlog.o xlogutils.o rmgr.o slru.o subtrans.o multixact.o twophase.o twophase_rmgr.o include $(top_srcdir)/src/backend/common.mk --- 12,18 ---- top_builddir = ../../../.. include $(top_builddir)/src/Makefile.global ! OBJS = clog.o transam.o varsup.o xact.o xlog.o xlogutils.o rmgr.o slru.o subtrans.o multixact.o twophase.o twophase_rmgr.o readahead.o include $(top_srcdir)/src/backend/common.mk diff -rcN Postgresql-CVS-20090313.org/src/backend/access/transam/readahead.c Postgresql-CVS-20090313/src/backend/access/transam/readahead.c *** Postgresql-CVS-20090313.org/src/backend/access/transam/readahead.c 1970-01-01 09:00:00.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/transam/readahead.c 2009-03-13 16:42:06.000000000 +0900 *************** *** 0 **** --- 1,233 ---- + /*------------------------------------------------------------------------- + * + * readahead.c + * Store information of data pages which should be read ahead. + * + * Original coding 2008, Koichi Suzuki. + * + * Portions Copyright (c) 1998-2009, PostgreSQL Global Development Group + * + *------------------------------------------------------------------------- + */ + + #include + #include + #include + #include + + #include "postgres.h" + #include "access/xlog_internal.h" + #include "catalog/catalog.h" + #include "storage/relfilenode.h" + #include "storage/block.h" + #include "storage/smgr.h" + + /* + * Information about the data page which will be read ahead. + */ + struct XLogReadAhead { + /* + * The physical location of the data page. + */ + RelFileNode node; + BlockNumber blkno; + + /* + * xrecoff is the byte offset of location in the WAL segment file as + * defined in xlogdefs.h. The read ahead command does not deal with more + * than one WAL segment file at once, and xlogid is not going to be changed + * during read-ahead. This is why we need only xrecoff. + */ + uint32 xrecoff; + + /* + * has_fpw indicates whether an WAL record contains full page write or not. + * This is used to skip unnecessary read-aheads. + */ + bool has_fpw; + }; + typedef struct XLogReadAhead XLogReadAhead; + + /* + * ReadAheadQueueSize is the initail size of XLogReadAhead queue. + * When the number of XLogReadAhead reaches this amount, we execute readahead. + * Queue uses 16MB. + */ + #define ReadAheadQueueSize (16 * 1024 * 1024) + + /* The queue for XLogReadAhead entries. */ + static XLogReadAhead *ReadAheadQueue = NULL; + + /* The number of XLogReadAhead entries currently used. */ + static uint32 ReadAheadQueueUsed = 0; + + /* prototype of local function */ + static int ReadAheadCompare(const void *l, const void *r); + + /* + * Initialize the buffer for storing information about data pages + */ + void + ReadAheadInit(void) + { + /* Allocate a buffer for storing information about data pages */ + ReadAheadQueue = (XLogReadAhead *) malloc(ReadAheadQueueSize); + Assert(ReadAheadQueue != NULL); + if (ReadAheadQueue == NULL) + elog(FATAL, "Memory not available for xlog readahead, need %d Megabytes", ReadAheadQueueSize/(1024*1024)); + } + + /* + * Append a new XLogReadAhead entry to the queue + * + * If XLogReadAhead queue is fullfilled, prefetch first and add ReadAheadQueue + * to empty queue. + */ + void + ReadAheadAddEntry(RelFileNode node, BlockNumber blkno, uint32 xrecoff, + bool has_fpw) + { + /* all entries are used, so prefetch pages and make the queue empty */ + if (ReadAheadQueueUsed >= ReadAheadQueueSize / sizeof(XLogReadAhead)) + { + ReadAheadExecute(); + } + + /* Append a new XLogReadAhead ReadAheadQueue to the queue. */ + ReadAheadQueue[ReadAheadQueueUsed].node = node; + ReadAheadQueue[ReadAheadQueueUsed].blkno = blkno; + ReadAheadQueue[ReadAheadQueueUsed].xrecoff = xrecoff; + ReadAheadQueue[ReadAheadQueueUsed].has_fpw = has_fpw; + + ReadAheadQueueUsed++; + } + + /* + * ReadAhead queue availability check + * + * If the XLogReadAhead queue has enough room for appending more num of + * XLogReadAhead, + * return true. If it does not, try to double the queue. + * If new queue could't be allocated, return false. + */ + bool + ReadAheadHasRoom(int num) + { + return (ReadAheadQueueUsed + num <= ReadAheadQueueSize / + sizeof(XLogReadAhead)); + } + + /* + * Check whether info1 and info2 point same data page. + */ + #define IS_SAME_PAGE(info1, info2) \ + (RelFileNodeEquals((info1).node, (info2).node) && \ + (info1).blkno == (info2).blkno) + + /* + * Execute read ahead data pages + * + * Before we actually read ahead data pages, sort the XLogReadAhead in the queue + * for avoiding duplicated disk access and hopefully, reducing seek time. + * We also skip read ahead data pages which has full page write. + * + * For performance, we keep file opened until reading another file. + */ + void + ReadAheadExecute(void) + { + int i; + SMgrRelation reln; + XLogReadAhead last_entry = { { 0, 0, 0, }, 0, 0, false }; + + ereport(DEBUG1, (errmsg("%d blocks are prefetch candidate", + ReadAheadQueueUsed))); + + /* Sort the XLogReadAhead queue for effective disk access. */ + qsort(ReadAheadQueue, ReadAheadQueueUsed, sizeof(XLogReadAhead), + ReadAheadCompare); + + for (i = 0; i < ReadAheadQueueUsed; i++) + { + /* Do read ahead once per a page if it doesn't have full page write. */ + if (IS_SAME_PAGE(last_entry, ReadAheadQueue[i]) || + ReadAheadQueue[i].has_fpw) + { + last_entry = ReadAheadQueue[i]; + continue; + } + + /* Create SMgrRelation object */ + reln = smgropen(ReadAheadQueue[i].node); + + /* Read ahead with prefetch API */ + smgrprefetch(reln, MAIN_FORKNUM, ReadAheadQueue[i].blkno); + + /* Store XLogReadAhead to skip duplicate pages. */ + last_entry = ReadAheadQueue[i]; + } + ReadAheadQueueUsed = 0; + } + + /* + * Compare two XLogReadAhead objects + * + * When l > r, then return 1, l == r, then return 0, and l < r, then return -1. + * The priority of comparison clauses shows below; + * 1. node.spcNode + * 2. node.dbNode + * 3. node.relNode + * 4. blkno + * 5. xrecoff + */ + static int + ReadAheadCompare(const void *l, const void *r) + { + XLogReadAhead *left = (XLogReadAhead *)l; + XLogReadAhead *right = (XLogReadAhead *)r; + + /* compare node.spcNode */ + if (left->node.spcNode > right->node.spcNode) + return 1; + else if (left->node.spcNode < right->node.spcNode) + return -1; + + /* compare node.dbNode */ + if (left->node.dbNode > right->node.dbNode) + return 1; + else if (left->node.dbNode < right->node.dbNode) + return -1; + + /* compare node.relNode */ + if (left->node.relNode > right->node.relNode) + return 1; + else if (left->node.relNode < right->node.relNode) + return -1; + + /* compare blkno */ + if (left->blkno > right->blkno) + return 1; + else if (left->blkno < right->blkno) + return -1; + + /* compare xrecoff */ + if (left->xrecoff > right->xrecoff) + return 1; + else if (left->xrecoff < right->xrecoff) + return -1; + + /* These two XLogReadAhead are same. */ + return 0; + } + + /* + * Release ReadAheadQueue buffer + */ + void + ReadAheadFinish(void) + { + if (ReadAheadQueue) + { + free(ReadAheadQueue); + } + } diff -rcN Postgresql-CVS-20090313.org/src/backend/access/transam/readahead.c~ Postgresql-CVS-20090313/src/backend/access/transam/readahead.c~ *** Postgresql-CVS-20090313.org/src/backend/access/transam/readahead.c~ 1970-01-01 09:00:00.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/transam/readahead.c~ 2009-03-13 16:37:09.000000000 +0900 *************** *** 0 **** --- 1,231 ---- + /*------------------------------------------------------------------------- + * + * readahead.c + * Store information of data pages which should be read ahead. + * + * Original coding 2008, Koichi Suzuki. + * + * Portions Copyright (c) 1998-2009, PostgreSQL Global Development Group + * + *------------------------------------------------------------------------- + */ + + #include + #include + #include + #include + + #include "postgres.h" + #include "access/xlog_internal.h" + #include "catalog/catalog.h" + #include "storage/relfilenode.h" + #include "storage/block.h" + #include "storage/smgr.h" + + /* + * Information about the data page which will be read ahead. + */ + struct XLogReadAhead { + /* + * The physical location of the data page. + */ + RelFileNode node; + BlockNumber blkno; + + /* + * xrecoff is the byte offset of location in the WAL segment file as + * defined in xlogdefs.h. The read ahead command does not deal with more + * than one WAL segment file at once, and xlogid is not going to be changed + * during read-ahead. This is why we need only xrecoff. + */ + uint32 xrecoff; + + /* + * has_fpw indicates whether an WAL record contains full page write or not. + * This is used to skip unnecessary read-aheads. + */ + bool has_fpw; + }; + typedef struct XLogReadAhead XLogReadAhead; + + /* + * ReadAheadQueueSize is the initail size of XLogReadAhead queue. + * When the number of XLogReadAhead reaches this amount, we execute readahead. + * Queue uses 16MB. + */ + #define ReadAheadQueueSize (16 * 1024 * 1024) + + /* The queue for XLogReadAhead entries. */ + static XLogReadAhead *ReadAheadQueue = NULL; + + /* The number of XLogReadAhead entries currently used. */ + static uint32 ReadAheadQueueUsed = 0; + + /* prototype of local function */ + static int ReadAheadCompare(const void *l, const void *r); + + /* + * Initialize the buffer for storing information about data pages + */ + void + ReadAheadInit(void) + { + /* Allocate a buffer for storing information about data pages */ + ReadAheadQueue = (XLogReadAhead *) malloc(ReadAheadQueueSize); + Assert(ReadAheadQueue != NULL); + } + + /* + * Append a new XLogReadAhead entry to the queue + * + * If XLogReadAhead queue is fullfilled, prefetch first and add ReadAheadQueue + * to empty queue. + */ + void + ReadAheadAddEntry(RelFileNode node, BlockNumber blkno, uint32 xrecoff, + bool has_fpw) + { + /* all entries are used, so prefetch pages and make the queue empty */ + if (ReadAheadQueueUsed >= ReadAheadQueueSize / sizeof(XLogReadAhead)) + { + ReadAheadExecute(); + } + + /* Append a new XLogReadAhead ReadAheadQueue to the queue. */ + ReadAheadQueue[ReadAheadQueueUsed].node = node; + ReadAheadQueue[ReadAheadQueueUsed].blkno = blkno; + ReadAheadQueue[ReadAheadQueueUsed].xrecoff = xrecoff; + ReadAheadQueue[ReadAheadQueueUsed].has_fpw = has_fpw; + + ReadAheadQueueUsed++; + } + + /* + * ReadAhead queue availability check + * + * If the XLogReadAhead queue has enough room for appending more num of + * XLogReadAhead, + * return true. If it does not, try to double the queue. + * If new queue could't be allocated, return false. + */ + bool + ReadAheadHasRoom(int num) + { + return (ReadAheadQueueUsed + num <= ReadAheadQueueSize / + sizeof(XLogReadAhead)); + } + + /* + * Check whether info1 and info2 point same data page. + */ + #define IS_SAME_PAGE(info1, info2) \ + (RelFileNodeEquals((info1).node, (info2).node) && \ + (info1).blkno == (info2).blkno) + + /* + * Execute read ahead data pages + * + * Before we actually read ahead data pages, sort the XLogReadAhead in the queue + * for avoiding duplicated disk access and hopefully, reducing seek time. + * We also skip read ahead data pages which has full page write. + * + * For performance, we keep file opened until reading another file. + */ + void + ReadAheadExecute(void) + { + int i; + SMgrRelation reln; + XLogReadAhead last_entry = { { 0, 0, 0, }, 0, 0, false }; + + ereport(DEBUG1, (errmsg("%d blocks are prefetch candidate", + ReadAheadQueueUsed))); + + /* Sort the XLogReadAhead queue for effective disk access. */ + qsort(ReadAheadQueue, ReadAheadQueueUsed, sizeof(XLogReadAhead), + ReadAheadCompare); + + for (i = 0; i < ReadAheadQueueUsed; i++) + { + /* Do read ahead once per a page if it doesn't have full page write. */ + if (IS_SAME_PAGE(last_entry, ReadAheadQueue[i]) || + ReadAheadQueue[i].has_fpw) + { + last_entry = ReadAheadQueue[i]; + continue; + } + + /* Create SMgrRelation object */ + reln = smgropen(ReadAheadQueue[i].node); + + /* Read ahead with prefetch API */ + smgrprefetch(reln, MAIN_FORKNUM, ReadAheadQueue[i].blkno); + + /* Store XLogReadAhead to skip duplicate pages. */ + last_entry = ReadAheadQueue[i]; + } + ReadAheadQueueUsed = 0; + } + + /* + * Compare two XLogReadAhead objects + * + * When l > r, then return 1, l == r, then return 0, and l < r, then return -1. + * The priority of comparison clauses shows below; + * 1. node.spcNode + * 2. node.dbNode + * 3. node.relNode + * 4. blkno + * 5. xrecoff + */ + static int + ReadAheadCompare(const void *l, const void *r) + { + XLogReadAhead *left = (XLogReadAhead *)l; + XLogReadAhead *right = (XLogReadAhead *)r; + + /* compare node.spcNode */ + if (left->node.spcNode > right->node.spcNode) + return 1; + else if (left->node.spcNode < right->node.spcNode) + return -1; + + /* compare node.dbNode */ + if (left->node.dbNode > right->node.dbNode) + return 1; + else if (left->node.dbNode < right->node.dbNode) + return -1; + + /* compare node.relNode */ + if (left->node.relNode > right->node.relNode) + return 1; + else if (left->node.relNode < right->node.relNode) + return -1; + + /* compare blkno */ + if (left->blkno > right->blkno) + return 1; + else if (left->blkno < right->blkno) + return -1; + + /* compare xrecoff */ + if (left->xrecoff > right->xrecoff) + return 1; + else if (left->xrecoff < right->xrecoff) + return -1; + + /* These two XLogReadAhead are same. */ + return 0; + } + + /* + * Release ReadAheadQueue buffer + */ + void + ReadAheadFinish(void) + { + if (ReadAheadQueue) + { + free(ReadAheadQueue); + } + } diff -rcN Postgresql-CVS-20090313.org/src/backend/access/transam/rmgr.c Postgresql-CVS-20090313/src/backend/access/transam/rmgr.c *** Postgresql-CVS-20090313.org/src/backend/access/transam/rmgr.c 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/transam/rmgr.c 2009-03-13 16:37:09.000000000 +0900 *************** *** 24,43 **** const RmgrData RmgrTable[RM_MAX_ID + 1] = { ! {"XLOG", xlog_redo, xlog_desc, NULL, NULL, NULL}, ! {"Transaction", xact_redo, xact_desc, NULL, NULL, NULL}, ! {"Storage", smgr_redo, smgr_desc, NULL, NULL, NULL}, ! {"CLOG", clog_redo, clog_desc, NULL, NULL, NULL}, ! {"Database", dbase_redo, dbase_desc, NULL, NULL, NULL}, ! {"Tablespace", tblspc_redo, tblspc_desc, NULL, NULL, NULL}, ! {"MultiXact", multixact_redo, multixact_desc, NULL, NULL, NULL}, ! {"Reserved 7", NULL, NULL, NULL, NULL, NULL}, ! {"Reserved 8", NULL, NULL, NULL, NULL, NULL}, ! {"Heap2", heap2_redo, heap2_desc, NULL, NULL, NULL}, ! {"Heap", heap_redo, heap_desc, NULL, NULL, NULL}, ! {"Btree", btree_redo, btree_desc, btree_xlog_startup, btree_xlog_cleanup, btree_safe_restartpoint}, ! {"Hash", hash_redo, hash_desc, NULL, NULL, NULL}, ! {"Gin", gin_redo, gin_desc, gin_xlog_startup, gin_xlog_cleanup, gin_safe_restartpoint}, ! {"Gist", gist_redo, gist_desc, gist_xlog_startup, gist_xlog_cleanup, gist_safe_restartpoint}, ! {"Sequence", seq_redo, seq_desc, NULL, NULL, NULL} }; --- 24,43 ---- const RmgrData RmgrTable[RM_MAX_ID + 1] = { ! {"XLOG", xlog_redo, xlog_desc, NULL, NULL, NULL, NULL}, ! {"Transaction", xact_redo, xact_desc, NULL, NULL, NULL, NULL}, ! {"Storage", smgr_redo, smgr_desc, NULL, NULL, NULL, NULL}, ! {"CLOG", clog_redo, clog_desc, NULL, NULL, NULL, NULL}, ! {"Database", dbase_redo, dbase_desc, NULL, NULL, NULL, NULL}, ! {"Tablespace", tblspc_redo, tblspc_desc, NULL, NULL, NULL, NULL}, ! {"MultiXact", multixact_redo, multixact_desc, NULL, NULL, NULL, NULL}, ! {"Reserved 7", NULL, NULL, NULL, NULL, NULL, NULL}, ! {"Reserved 8", NULL, NULL, NULL, NULL, NULL, NULL}, ! {"Heap2", heap2_redo, heap2_desc, NULL, NULL, NULL, heap2_readahead}, ! {"Heap", heap_redo, heap_desc, NULL, NULL, NULL, heap_readahead}, ! {"Btree", btree_redo, btree_desc, btree_xlog_startup, btree_xlog_cleanup, btree_safe_restartpoint, btree_readahead}, ! {"Hash", hash_redo, hash_desc, NULL, NULL, NULL, NULL}, ! {"Gin", gin_redo, gin_desc, gin_xlog_startup, gin_xlog_cleanup, gin_safe_restartpoint, gin_readahead}, ! {"Gist", gist_redo, gist_desc, gist_xlog_startup, gist_xlog_cleanup, gist_safe_restartpoint, gist_readahead}, ! {"Sequence", seq_redo, seq_desc, NULL, NULL, NULL, seq_readahead} }; diff -rcN Postgresql-CVS-20090313.org/src/backend/access/transam/xlog.c Postgresql-CVS-20090313/src/backend/access/transam/xlog.c *** Postgresql-CVS-20090313.org/src/backend/access/transam/xlog.c 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/transam/xlog.c 2009-03-13 16:39:42.000000000 +0900 *************** *** 382,387 **** --- 382,399 ---- static char *readRecordBuf = NULL; static uint32 readRecordBufSize = 0; + /* + * Buffer for queued WAL records (fixed size) + * + * This buffer is used for holding WAL records and their LSNs. When the all WAL + * records of one WAL segment file are read, redo them and make the buffer + * empty. Therefore, twice of XLogSegSize, determined by the total size of WAL + * records and LSNs, must be enough for the buffer. + */ + #define RECORD_QUEUE_BUF_SIZE (XLogSegSize * 2) + static char *RecordQueueBuf = NULL; + static uint32 RecordQueueBufUsed = 0; + /* State information for XLOG reading */ static XLogRecPtr ReadRecPtr; /* start of last record read */ static XLogRecPtr EndRecPtr; /* end+1 of last record read */ *************** *** 442,447 **** --- 454,462 ---- static void rm_redo_error_callback(void *arg); static int get_sync_bit(int method); + static void PushRecord(XLogRecPtr lsn, XLogRecord *record); + static void PushReadAhead(XLogRecPtr lsn, XLogRecord *record); + static void RedoRecords(void); /* * Insert an XLOG record having the specified RMID and info bytes, *************** *** 2365,2370 **** --- 2380,2387 ---- ListCell *cell; int fd; + ereport(DEBUG1, (errmsg("XLOG switch to %X/%X", log, seg))); + /* * Loop looking for a suitable timeline ID: we might need to read any of * the timelines listed in expectedTLIs. *************** *** 2386,2391 **** --- 2403,2415 ---- if (InArchiveRecovery) { + /* + * Wait until next WAL segment file. It might takes long time. + * Therefore, redo with stored WAL records and LSNs here. + */ + ereport(DEBUG1, (errmsg("XLOG will be switched"))); + RedoRecords(); + /* Report recovery progress in PS display */ snprintf(activitymsg, sizeof(activitymsg), "waiting for %s", xlogfname); *************** *** 3427,3432 **** --- 3451,3463 ---- return (XLogRecord *) buffer; next_record_is_invalid:; + /* + * Reached to unused area of current WAL segment file, redo all of WAL + * records in the queue. + */ + ereport(DEBUG1, (errmsg("next record is invalid(maybe unused area)"))); + RedoRecords(); + if (readFile >= 0) { close(readFile); *************** *** 4944,4949 **** --- 4975,4991 ---- ValidateXLOGDirectoryStructure(); /* + * To postpone the actual redo, store WAL records and EndRecPtrs. + * Therefore, this buffer must be allocated here because the buffer + * will be used by RedoRecords(); ReadRecord() may call RedoRecords(). + */ + RecordQueueBuf = (char *) malloc(RECORD_QUEUE_BUF_SIZE); + Assert(RecordQueueBuf != NULL); + + /* Allocate the buffer for storing information about data pages. */ + ReadAheadInit(); + + /* * Initialize on the assumption we want to recover to the same timeline * that's active according to pg_control. */ *************** *** 5157,5163 **** { bool recoveryContinue = true; bool recoveryApply = true; - ErrorContextCallback errcontext; InRedo = true; ereport(LOG, --- 5199,5204 ---- *************** *** 5199,5228 **** break; } - /* Setup error traceback support for ereport() */ - errcontext.callback = rm_redo_error_callback; - errcontext.arg = (void *) record; - errcontext.previous = error_context_stack; - error_context_stack = &errcontext; - - /* nextXid must be beyond record's xid */ - if (TransactionIdFollowsOrEquals(record->xl_xid, - ShmemVariableCache->nextXid)) - { - ShmemVariableCache->nextXid = record->xl_xid; - TransactionIdAdvance(ShmemVariableCache->nextXid); - } - - RmgrTable[record->xl_rmid].rm_redo(EndRecPtr, record); ! /* Pop the error context stack */ ! error_context_stack = errcontext.previous; LastRec = ReadRecPtr; record = ReadRecord(NULL, LOG); } while (record != NULL && recoveryContinue); /* * end of main redo apply loop */ --- 5240,5274 ---- break; } ! /* ! * Push WAL record in WAL record buffer with its LSN for ! * delayed redo. ! * If the WAL record queue is full, redo all WAL records in the ! * queue and make the queue empty. ! */ ! ereport(DEBUG1, ! (errmsg("WAL record queue is used %d(%d) bytes at %X/%08X.", ! RecordQueueBufUsed, record->xl_tot_len, ! EndRecPtr.xlogid, EndRecPtr.xrecoff))); ! PushRecord(EndRecPtr, record); ! ! /* ! * Push page information to prefetch later. ! * If no more space, redo all records in queue and make the ! * queue empty. ! */ ! PushReadAhead(EndRecPtr, record); LastRec = ReadRecPtr; record = ReadRecord(NULL, LOG); } while (record != NULL && recoveryContinue); + /* All WAL records are read, redo all queued WAL records. */ + ereport(DEBUG1, (errmsg("end of redo apply loop"))); + RedoRecords(); + /* * end of main redo apply loop */ *************** *** 5444,5449 **** --- 5490,5591 ---- readRecordBuf = NULL; readRecordBufSize = 0; } + if (RecordQueueBuf) + { + free(RecordQueueBuf); + RecordQueueBufUsed = 0; + ReadAheadFinish(); + } + } + + /* + * Push the pair of WAL record and its LSN. + * Both WAL records and LSNs are aligned as same as WAL segment file. + */ + static void + PushRecord(XLogRecPtr lsn, XLogRecord *record) + { + Assert(record); + + if (RecordQueueBufUsed + MAXALIGN(sizeof(XLogRecPtr)) + + MAXALIGN(record->xl_tot_len) > RECORD_QUEUE_BUF_SIZE) + { + ereport(DEBUG1, (errmsg("WAL record queue is full."))); + RedoRecords(); + } + + memcpy(RecordQueueBuf + RecordQueueBufUsed, &lsn, sizeof(XLogRecPtr)); + RecordQueueBufUsed += MAXALIGN(sizeof(XLogRecPtr)); + memcpy(RecordQueueBuf + RecordQueueBufUsed, record, record->xl_tot_len); + RecordQueueBufUsed += MAXALIGN(record->xl_tot_len); + } + + /* + * Push page information to readahead module. + */ + static void + PushReadAhead(XLogRecPtr lsn, XLogRecord *record) + { + Assert(record); + + if (!RmgrTable[record->xl_rmid].rm_readahead) + return; + + while (!RmgrTable[record->xl_rmid].rm_readahead(lsn, record)) + { + ereport(DEBUG1, (errmsg("ReadAhead queue is full."))); + RedoRecords(); + } + } + + /* + * Redo all WAL records in the queue and make the it empty. + */ + static void + RedoRecords(void) + { + ErrorContextCallback errcontext; + uint32 off = 0; + + /* Readahead data pages which will be modified during redo. */ + ReadAheadExecute(); + + while (off < RecordQueueBufUsed) + { + XLogRecPtr lsn; + XLogRecord *record; + + /* Extract LSN and WAL record image from local buffer. */ + memcpy(&lsn, RecordQueueBuf + off, sizeof(XLogRecPtr)); + off += MAXALIGN(sizeof(XLogRecPtr)); + record = (XLogRecord *)(RecordQueueBuf + off); + + /* Setup error traceback support for ereport() */ + errcontext.callback = rm_redo_error_callback; + errcontext.arg = (void *) record; + errcontext.previous = error_context_stack; + error_context_stack = &errcontext; + + /* nextXid must be beyond record's xid */ + if (TransactionIdFollowsOrEquals(record->xl_xid, + ShmemVariableCache->nextXid)) + { + ShmemVariableCache->nextXid = record->xl_xid; + TransactionIdAdvance(ShmemVariableCache->nextXid); + } + + /* Redo with WAL record and its LSN. */ + RmgrTable[record->xl_rmid].rm_redo(lsn, record); + + /* Pop the error context stack */ + error_context_stack = errcontext.previous; + + off += MAXALIGN(record->xl_tot_len); + } + + /* Make RecordQueueBuf empty. */ + MemSet(RecordQueueBuf, 0, sizeof(RecordQueueBuf)); + RecordQueueBufUsed = 0; } /* diff -rcN Postgresql-CVS-20090313.org/src/backend/access/transam/xlog.c.orig Postgresql-CVS-20090313/src/backend/access/transam/xlog.c.orig *** Postgresql-CVS-20090313.org/src/backend/access/transam/xlog.c.orig 1970-01-01 09:00:00.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/transam/xlog.c.orig 2009-03-13 04:02:50.000000000 +0900 *************** *** 0 **** --- 1,7229 ---- + /*------------------------------------------------------------------------- + * + * xlog.c + * PostgreSQL transaction log manager + * + * + * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.329 2009/01/23 11:19:34 heikki Exp $ + * + *------------------------------------------------------------------------- + */ + + #include "postgres.h" + + #include + #include + #include + #include + #include + #include + #include + #include + + #include "access/clog.h" + #include "access/multixact.h" + #include "access/subtrans.h" + #include "access/transam.h" + #include "access/tuptoaster.h" + #include "access/twophase.h" + #include "access/xact.h" + #include "access/xlog_internal.h" + #include "access/xlogutils.h" + #include "catalog/catversion.h" + #include "catalog/pg_control.h" + #include "catalog/pg_type.h" + #include "funcapi.h" + #include "miscadmin.h" + #include "pgstat.h" + #include "postmaster/bgwriter.h" + #include "storage/bufmgr.h" + #include "storage/fd.h" + #include "storage/ipc.h" + #include "storage/pmsignal.h" + #include "storage/procarray.h" + #include "storage/smgr.h" + #include "storage/spin.h" + #include "utils/builtins.h" + #include "utils/guc.h" + #include "utils/ps_status.h" + #include "pg_trace.h" + + + /* File path names (all relative to $PGDATA) */ + #define BACKUP_LABEL_FILE "backup_label" + #define BACKUP_LABEL_OLD "backup_label.old" + #define RECOVERY_COMMAND_FILE "recovery.conf" + #define RECOVERY_COMMAND_DONE "recovery.done" + + + /* User-settable parameters */ + int CheckPointSegments = 3; + int XLOGbuffers = 8; + int XLogArchiveTimeout = 0; + bool XLogArchiveMode = false; + char *XLogArchiveCommand = NULL; + bool fullPageWrites = true; + bool log_checkpoints = false; + int sync_method = DEFAULT_SYNC_METHOD; + + #ifdef WAL_DEBUG + bool XLOG_DEBUG = false; + #endif + + /* + * XLOGfileslop is the maximum number of preallocated future XLOG segments. + * When we are done with an old XLOG segment file, we will recycle it as a + * future XLOG segment as long as there aren't already XLOGfileslop future + * segments; else we'll delete it. This could be made a separate GUC + * variable, but at present I think it's sufficient to hardwire it as + * 2*CheckPointSegments+1. Under normal conditions, a checkpoint will free + * no more than 2*CheckPointSegments log segments, and we want to recycle all + * of them; the +1 allows boundary cases to happen without wasting a + * delete/create-segment cycle. + */ + #define XLOGfileslop (2*CheckPointSegments + 1) + + /* + * GUC support + */ + const struct config_enum_entry sync_method_options[] = { + {"fsync", SYNC_METHOD_FSYNC, false}, + #ifdef HAVE_FSYNC_WRITETHROUGH + {"fsync_writethrough", SYNC_METHOD_FSYNC_WRITETHROUGH, false}, + #endif + #ifdef HAVE_FDATASYNC + {"fdatasync", SYNC_METHOD_FDATASYNC, false}, + #endif + #ifdef OPEN_SYNC_FLAG + {"open_sync", SYNC_METHOD_OPEN, false}, + #endif + #ifdef OPEN_DATASYNC_FLAG + {"open_datasync", SYNC_METHOD_OPEN_DSYNC, false}, + #endif + {NULL, 0, false} + }; + + /* + * Statistics for current checkpoint are collected in this global struct. + * Because only the background writer or a stand-alone backend can perform + * checkpoints, this will be unused in normal backends. + */ + CheckpointStatsData CheckpointStats; + + /* + * ThisTimeLineID will be same in all backends --- it identifies current + * WAL timeline for the database system. + */ + TimeLineID ThisTimeLineID = 0; + + /* Are we doing recovery from XLOG? */ + bool InRecovery = false; + + /* Are we recovering using offline XLOG archives? */ + static bool InArchiveRecovery = false; + + /* Was the last xlog file restored from archive, or local? */ + static bool restoredFromArchive = false; + + /* options taken from recovery.conf */ + static char *recoveryRestoreCommand = NULL; + static bool recoveryTarget = false; + static bool recoveryTargetExact = false; + static bool recoveryTargetInclusive = true; + static bool recoveryLogRestartpoints = false; + static TransactionId recoveryTargetXid; + static TimestampTz recoveryTargetTime; + static TimestampTz recoveryLastXTime = 0; + + /* if recoveryStopsHere returns true, it saves actual stop xid/time here */ + static TransactionId recoveryStopXid; + static TimestampTz recoveryStopTime; + static bool recoveryStopAfter; + + /* + * During normal operation, the only timeline we care about is ThisTimeLineID. + * During recovery, however, things are more complicated. To simplify life + * for rmgr code, we keep ThisTimeLineID set to the "current" timeline as we + * scan through the WAL history (that is, it is the line that was active when + * the currently-scanned WAL record was generated). We also need these + * timeline values: + * + * recoveryTargetTLI: the desired timeline that we want to end in. + * + * expectedTLIs: an integer list of recoveryTargetTLI and the TLIs of + * its known parents, newest first (so recoveryTargetTLI is always the + * first list member). Only these TLIs are expected to be seen in the WAL + * segments we read, and indeed only these TLIs will be considered as + * candidate WAL files to open at all. + * + * curFileTLI: the TLI appearing in the name of the current input WAL file. + * (This is not necessarily the same as ThisTimeLineID, because we could + * be scanning data that was copied from an ancestor timeline when the current + * file was created.) During a sequential scan we do not allow this value + * to decrease. + */ + static TimeLineID recoveryTargetTLI; + static List *expectedTLIs; + static TimeLineID curFileTLI; + + /* + * ProcLastRecPtr points to the start of the last XLOG record inserted by the + * current backend. It is updated for all inserts. XactLastRecEnd points to + * end+1 of the last record, and is reset when we end a top-level transaction, + * or start a new one; so it can be used to tell if the current transaction has + * created any XLOG records. + */ + static XLogRecPtr ProcLastRecPtr = {0, 0}; + + XLogRecPtr XactLastRecEnd = {0, 0}; + + /* + * RedoRecPtr is this backend's local copy of the REDO record pointer + * (which is almost but not quite the same as a pointer to the most recent + * CHECKPOINT record). We update this from the shared-memory copy, + * XLogCtl->Insert.RedoRecPtr, whenever we can safely do so (ie, when we + * hold the Insert lock). See XLogInsert for details. We are also allowed + * to update from XLogCtl->Insert.RedoRecPtr if we hold the info_lck; + * see GetRedoRecPtr. A freshly spawned backend obtains the value during + * InitXLOGAccess. + */ + static XLogRecPtr RedoRecPtr; + + /*---------- + * Shared-memory data structures for XLOG control + * + * LogwrtRqst indicates a byte position that we need to write and/or fsync + * the log up to (all records before that point must be written or fsynced). + * LogwrtResult indicates the byte positions we have already written/fsynced. + * These structs are identical but are declared separately to indicate their + * slightly different functions. + * + * We do a lot of pushups to minimize the amount of access to lockable + * shared memory values. There are actually three shared-memory copies of + * LogwrtResult, plus one unshared copy in each backend. Here's how it works: + * XLogCtl->LogwrtResult is protected by info_lck + * XLogCtl->Write.LogwrtResult is protected by WALWriteLock + * XLogCtl->Insert.LogwrtResult is protected by WALInsertLock + * One must hold the associated lock to read or write any of these, but + * of course no lock is needed to read/write the unshared LogwrtResult. + * + * XLogCtl->LogwrtResult and XLogCtl->Write.LogwrtResult are both "always + * right", since both are updated by a write or flush operation before + * it releases WALWriteLock. The point of keeping XLogCtl->Write.LogwrtResult + * is that it can be examined/modified by code that already holds WALWriteLock + * without needing to grab info_lck as well. + * + * XLogCtl->Insert.LogwrtResult may lag behind the reality of the other two, + * but is updated when convenient. Again, it exists for the convenience of + * code that is already holding WALInsertLock but not the other locks. + * + * The unshared LogwrtResult may lag behind any or all of these, and again + * is updated when convenient. + * + * The request bookkeeping is simpler: there is a shared XLogCtl->LogwrtRqst + * (protected by info_lck), but we don't need to cache any copies of it. + * + * Note that this all works because the request and result positions can only + * advance forward, never back up, and so we can easily determine which of two + * values is "more up to date". + * + * info_lck is only held long enough to read/update the protected variables, + * so it's a plain spinlock. The other locks are held longer (potentially + * over I/O operations), so we use LWLocks for them. These locks are: + * + * WALInsertLock: must be held to insert a record into the WAL buffers. + * + * WALWriteLock: must be held to write WAL buffers to disk (XLogWrite or + * XLogFlush). + * + * ControlFileLock: must be held to read/update control file or create + * new log file. + * + * CheckpointLock: must be held to do a checkpoint (ensures only one + * checkpointer at a time; currently, with all checkpoints done by the + * bgwriter, this is just pro forma). + * + *---------- + */ + + typedef struct XLogwrtRqst + { + XLogRecPtr Write; /* last byte + 1 to write out */ + XLogRecPtr Flush; /* last byte + 1 to flush */ + } XLogwrtRqst; + + typedef struct XLogwrtResult + { + XLogRecPtr Write; /* last byte + 1 written out */ + XLogRecPtr Flush; /* last byte + 1 flushed */ + } XLogwrtResult; + + /* + * Shared state data for XLogInsert. + */ + typedef struct XLogCtlInsert + { + XLogwrtResult LogwrtResult; /* a recent value of LogwrtResult */ + XLogRecPtr PrevRecord; /* start of previously-inserted record */ + int curridx; /* current block index in cache */ + XLogPageHeader currpage; /* points to header of block in cache */ + char *currpos; /* current insertion point in cache */ + XLogRecPtr RedoRecPtr; /* current redo point for insertions */ + bool forcePageWrites; /* forcing full-page writes for PITR? */ + } XLogCtlInsert; + + /* + * Shared state data for XLogWrite/XLogFlush. + */ + typedef struct XLogCtlWrite + { + XLogwrtResult LogwrtResult; /* current value of LogwrtResult */ + int curridx; /* cache index of next block to write */ + pg_time_t lastSegSwitchTime; /* time of last xlog segment switch */ + } XLogCtlWrite; + + /* + * Total shared-memory state for XLOG. + */ + typedef struct XLogCtlData + { + /* Protected by WALInsertLock: */ + XLogCtlInsert Insert; + + /* Protected by info_lck: */ + XLogwrtRqst LogwrtRqst; + XLogwrtResult LogwrtResult; + uint32 ckptXidEpoch; /* nextXID & epoch of latest checkpoint */ + TransactionId ckptXid; + XLogRecPtr asyncCommitLSN; /* LSN of newest async commit */ + + /* Protected by WALWriteLock: */ + XLogCtlWrite Write; + + /* + * These values do not change after startup, although the pointed-to pages + * and xlblocks values certainly do. Permission to read/write the pages + * and xlblocks values depends on WALInsertLock and WALWriteLock. + */ + char *pages; /* buffers for unwritten XLOG pages */ + XLogRecPtr *xlblocks; /* 1st byte ptr-s + XLOG_BLCKSZ */ + int XLogCacheBlck; /* highest allocated xlog buffer index */ + TimeLineID ThisTimeLineID; + + slock_t info_lck; /* locks shared variables shown above */ + } XLogCtlData; + + static XLogCtlData *XLogCtl = NULL; + + /* + * We maintain an image of pg_control in shared memory. + */ + static ControlFileData *ControlFile = NULL; + + /* + * Macros for managing XLogInsert state. In most cases, the calling routine + * has local copies of XLogCtl->Insert and/or XLogCtl->Insert->curridx, + * so these are passed as parameters instead of being fetched via XLogCtl. + */ + + /* Free space remaining in the current xlog page buffer */ + #define INSERT_FREESPACE(Insert) \ + (XLOG_BLCKSZ - ((Insert)->currpos - (char *) (Insert)->currpage)) + + /* Construct XLogRecPtr value for current insertion point */ + #define INSERT_RECPTR(recptr,Insert,curridx) \ + ( \ + (recptr).xlogid = XLogCtl->xlblocks[curridx].xlogid, \ + (recptr).xrecoff = \ + XLogCtl->xlblocks[curridx].xrecoff - INSERT_FREESPACE(Insert) \ + ) + + #define PrevBufIdx(idx) \ + (((idx) == 0) ? XLogCtl->XLogCacheBlck : ((idx) - 1)) + + #define NextBufIdx(idx) \ + (((idx) == XLogCtl->XLogCacheBlck) ? 0 : ((idx) + 1)) + + /* + * Private, possibly out-of-date copy of shared LogwrtResult. + * See discussion above. + */ + static XLogwrtResult LogwrtResult = {{0, 0}, {0, 0}}; + + /* + * openLogFile is -1 or a kernel FD for an open log file segment. + * When it's open, openLogOff is the current seek offset in the file. + * openLogId/openLogSeg identify the segment. These variables are only + * used to write the XLOG, and so will normally refer to the active segment. + */ + static int openLogFile = -1; + static uint32 openLogId = 0; + static uint32 openLogSeg = 0; + static uint32 openLogOff = 0; + + /* + * These variables are used similarly to the ones above, but for reading + * the XLOG. Note, however, that readOff generally represents the offset + * of the page just read, not the seek position of the FD itself, which + * will be just past that page. + */ + static int readFile = -1; + static uint32 readId = 0; + static uint32 readSeg = 0; + static uint32 readOff = 0; + + /* Buffer for currently read page (XLOG_BLCKSZ bytes) */ + static char *readBuf = NULL; + + /* Buffer for current ReadRecord result (expandable) */ + static char *readRecordBuf = NULL; + static uint32 readRecordBufSize = 0; + + /* State information for XLOG reading */ + static XLogRecPtr ReadRecPtr; /* start of last record read */ + static XLogRecPtr EndRecPtr; /* end+1 of last record read */ + static XLogRecord *nextRecord = NULL; + static TimeLineID lastPageTLI = 0; + + static bool InRedo = false; + + + static void XLogArchiveNotify(const char *xlog); + static void XLogArchiveNotifySeg(uint32 log, uint32 seg); + static bool XLogArchiveCheckDone(const char *xlog); + static bool XLogArchiveIsBusy(const char *xlog); + static void XLogArchiveCleanup(const char *xlog); + static void readRecoveryCommandFile(void); + static void exitArchiveRecovery(TimeLineID endTLI, + uint32 endLogId, uint32 endLogSeg); + static bool recoveryStopsHere(XLogRecord *record, bool *includeThis); + static void CheckPointGuts(XLogRecPtr checkPointRedo, int flags); + + static bool XLogCheckBuffer(XLogRecData *rdata, bool doPageWrites, + XLogRecPtr *lsn, BkpBlock *bkpb); + static bool AdvanceXLInsertBuffer(bool new_segment); + static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible, bool xlog_switch); + static int XLogFileInit(uint32 log, uint32 seg, + bool *use_existent, bool use_lock); + static bool InstallXLogFileSegment(uint32 *log, uint32 *seg, char *tmppath, + bool find_free, int *max_advance, + bool use_lock); + static int XLogFileOpen(uint32 log, uint32 seg); + static int XLogFileRead(uint32 log, uint32 seg, int emode); + static void XLogFileClose(void); + static bool RestoreArchivedFile(char *path, const char *xlogfname, + const char *recovername, off_t expectedSize); + static void PreallocXlogFiles(XLogRecPtr endptr); + static void RemoveOldXlogFiles(uint32 log, uint32 seg, XLogRecPtr endptr); + static void ValidateXLOGDirectoryStructure(void); + static void CleanupBackupHistory(void); + static XLogRecord *ReadRecord(XLogRecPtr *RecPtr, int emode); + static bool ValidXLOGHeader(XLogPageHeader hdr, int emode); + static XLogRecord *ReadCheckpointRecord(XLogRecPtr RecPtr, int whichChkpt); + static List *readTimeLineHistory(TimeLineID targetTLI); + static bool existsTimeLineHistory(TimeLineID probeTLI); + static TimeLineID findNewestTimeLine(TimeLineID startTLI); + static void writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI, + TimeLineID endTLI, + uint32 endLogId, uint32 endLogSeg); + static void WriteControlFile(void); + static void ReadControlFile(void); + static char *str_time(pg_time_t tnow); + #ifdef WAL_DEBUG + static void xlog_outrec(StringInfo buf, XLogRecord *record); + #endif + static void issue_xlog_fsync(void); + static void pg_start_backup_callback(int code, Datum arg); + static bool read_backup_label(XLogRecPtr *checkPointLoc, + XLogRecPtr *minRecoveryLoc); + static void rm_redo_error_callback(void *arg); + static int get_sync_bit(int method); + + + /* + * Insert an XLOG record having the specified RMID and info bytes, + * with the body of the record being the data chunk(s) described by + * the rdata chain (see xlog.h for notes about rdata). + * + * Returns XLOG pointer to end of record (beginning of next record). + * This can be used as LSN for data pages affected by the logged action. + * (LSN is the XLOG point up to which the XLOG must be flushed to disk + * before the data page can be written out. This implements the basic + * WAL rule "write the log before the data".) + * + * NB: this routine feels free to scribble on the XLogRecData structs, + * though not on the data they reference. This is OK since the XLogRecData + * structs are always just temporaries in the calling code. + */ + XLogRecPtr + XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata) + { + XLogCtlInsert *Insert = &XLogCtl->Insert; + XLogRecord *record; + XLogContRecord *contrecord; + XLogRecPtr RecPtr; + XLogRecPtr WriteRqst; + uint32 freespace; + int curridx; + XLogRecData *rdt; + Buffer dtbuf[XLR_MAX_BKP_BLOCKS]; + bool dtbuf_bkp[XLR_MAX_BKP_BLOCKS]; + BkpBlock dtbuf_xlg[XLR_MAX_BKP_BLOCKS]; + XLogRecPtr dtbuf_lsn[XLR_MAX_BKP_BLOCKS]; + XLogRecData dtbuf_rdt1[XLR_MAX_BKP_BLOCKS]; + XLogRecData dtbuf_rdt2[XLR_MAX_BKP_BLOCKS]; + XLogRecData dtbuf_rdt3[XLR_MAX_BKP_BLOCKS]; + pg_crc32 rdata_crc; + uint32 len, + write_len; + unsigned i; + bool updrqst; + bool doPageWrites; + bool isLogSwitch = (rmid == RM_XLOG_ID && info == XLOG_SWITCH); + + /* info's high bits are reserved for use by me */ + if (info & XLR_INFO_MASK) + elog(PANIC, "invalid xlog info mask %02X", info); + + TRACE_POSTGRESQL_XLOG_INSERT(rmid, info); + + /* + * In bootstrap mode, we don't actually log anything but XLOG resources; + * return a phony record pointer. + */ + if (IsBootstrapProcessingMode() && rmid != RM_XLOG_ID) + { + RecPtr.xlogid = 0; + RecPtr.xrecoff = SizeOfXLogLongPHD; /* start of 1st chkpt record */ + return RecPtr; + } + + /* + * Here we scan the rdata chain, determine which buffers must be backed + * up, and compute the CRC values for the data. Note that the record + * header isn't added into the CRC initially since we don't know the final + * length or info bits quite yet. Thus, the CRC will represent the CRC of + * the whole record in the order "rdata, then backup blocks, then record + * header". + * + * We may have to loop back to here if a race condition is detected below. + * We could prevent the race by doing all this work while holding the + * insert lock, but it seems better to avoid doing CRC calculations while + * holding the lock. This means we have to be careful about modifying the + * rdata chain until we know we aren't going to loop back again. The only + * change we allow ourselves to make earlier is to set rdt->data = NULL in + * chain items we have decided we will have to back up the whole buffer + * for. This is OK because we will certainly decide the same thing again + * for those items if we do it over; doing it here saves an extra pass + * over the chain later. + */ + begin:; + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + dtbuf[i] = InvalidBuffer; + dtbuf_bkp[i] = false; + } + + /* + * Decide if we need to do full-page writes in this XLOG record: true if + * full_page_writes is on or we have a PITR request for it. Since we + * don't yet have the insert lock, forcePageWrites could change under us, + * but we'll recheck it once we have the lock. + */ + doPageWrites = fullPageWrites || Insert->forcePageWrites; + + INIT_CRC32(rdata_crc); + len = 0; + for (rdt = rdata;;) + { + if (rdt->buffer == InvalidBuffer) + { + /* Simple data, just include it */ + len += rdt->len; + COMP_CRC32(rdata_crc, rdt->data, rdt->len); + } + else + { + /* Find info for buffer */ + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + if (rdt->buffer == dtbuf[i]) + { + /* Buffer already referenced by earlier chain item */ + if (dtbuf_bkp[i]) + rdt->data = NULL; + else if (rdt->data) + { + len += rdt->len; + COMP_CRC32(rdata_crc, rdt->data, rdt->len); + } + break; + } + if (dtbuf[i] == InvalidBuffer) + { + /* OK, put it in this slot */ + dtbuf[i] = rdt->buffer; + if (XLogCheckBuffer(rdt, doPageWrites, + &(dtbuf_lsn[i]), &(dtbuf_xlg[i]))) + { + dtbuf_bkp[i] = true; + rdt->data = NULL; + } + else if (rdt->data) + { + len += rdt->len; + COMP_CRC32(rdata_crc, rdt->data, rdt->len); + } + break; + } + } + if (i >= XLR_MAX_BKP_BLOCKS) + elog(PANIC, "can backup at most %d blocks per xlog record", + XLR_MAX_BKP_BLOCKS); + } + /* Break out of loop when rdt points to last chain item */ + if (rdt->next == NULL) + break; + rdt = rdt->next; + } + + /* + * Now add the backup block headers and data into the CRC + */ + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + if (dtbuf_bkp[i]) + { + BkpBlock *bkpb = &(dtbuf_xlg[i]); + char *page; + + COMP_CRC32(rdata_crc, + (char *) bkpb, + sizeof(BkpBlock)); + page = (char *) BufferGetBlock(dtbuf[i]); + if (bkpb->hole_length == 0) + { + COMP_CRC32(rdata_crc, + page, + BLCKSZ); + } + else + { + /* must skip the hole */ + COMP_CRC32(rdata_crc, + page, + bkpb->hole_offset); + COMP_CRC32(rdata_crc, + page + (bkpb->hole_offset + bkpb->hole_length), + BLCKSZ - (bkpb->hole_offset + bkpb->hole_length)); + } + } + } + + /* + * NOTE: We disallow len == 0 because it provides a useful bit of extra + * error checking in ReadRecord. This means that all callers of + * XLogInsert must supply at least some not-in-a-buffer data. However, we + * make an exception for XLOG SWITCH records because we don't want them to + * ever cross a segment boundary. + */ + if (len == 0 && !isLogSwitch) + elog(PANIC, "invalid xlog record length %u", len); + + START_CRIT_SECTION(); + + /* Now wait to get insert lock */ + LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); + + /* + * Check to see if my RedoRecPtr is out of date. If so, may have to go + * back and recompute everything. This can only happen just after a + * checkpoint, so it's better to be slow in this case and fast otherwise. + * + * If we aren't doing full-page writes then RedoRecPtr doesn't actually + * affect the contents of the XLOG record, so we'll update our local copy + * but not force a recomputation. + */ + if (!XLByteEQ(RedoRecPtr, Insert->RedoRecPtr)) + { + Assert(XLByteLT(RedoRecPtr, Insert->RedoRecPtr)); + RedoRecPtr = Insert->RedoRecPtr; + + if (doPageWrites) + { + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + if (dtbuf[i] == InvalidBuffer) + continue; + if (dtbuf_bkp[i] == false && + XLByteLE(dtbuf_lsn[i], RedoRecPtr)) + { + /* + * Oops, this buffer now needs to be backed up, but we + * didn't think so above. Start over. + */ + LWLockRelease(WALInsertLock); + END_CRIT_SECTION(); + goto begin; + } + } + } + } + + /* + * Also check to see if forcePageWrites was just turned on; if we weren't + * already doing full-page writes then go back and recompute. (If it was + * just turned off, we could recompute the record without full pages, but + * we choose not to bother.) + */ + if (Insert->forcePageWrites && !doPageWrites) + { + /* Oops, must redo it with full-page data */ + LWLockRelease(WALInsertLock); + END_CRIT_SECTION(); + goto begin; + } + + /* + * Make additional rdata chain entries for the backup blocks, so that we + * don't need to special-case them in the write loop. Note that we have + * now irrevocably changed the input rdata chain. At the exit of this + * loop, write_len includes the backup block data. + * + * Also set the appropriate info bits to show which buffers were backed + * up. The i'th XLR_SET_BKP_BLOCK bit corresponds to the i'th distinct + * buffer value (ignoring InvalidBuffer) appearing in the rdata chain. + */ + write_len = len; + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + BkpBlock *bkpb; + char *page; + + if (!dtbuf_bkp[i]) + continue; + + info |= XLR_SET_BKP_BLOCK(i); + + bkpb = &(dtbuf_xlg[i]); + page = (char *) BufferGetBlock(dtbuf[i]); + + rdt->next = &(dtbuf_rdt1[i]); + rdt = rdt->next; + + rdt->data = (char *) bkpb; + rdt->len = sizeof(BkpBlock); + write_len += sizeof(BkpBlock); + + rdt->next = &(dtbuf_rdt2[i]); + rdt = rdt->next; + + if (bkpb->hole_length == 0) + { + rdt->data = page; + rdt->len = BLCKSZ; + write_len += BLCKSZ; + rdt->next = NULL; + } + else + { + /* must skip the hole */ + rdt->data = page; + rdt->len = bkpb->hole_offset; + write_len += bkpb->hole_offset; + + rdt->next = &(dtbuf_rdt3[i]); + rdt = rdt->next; + + rdt->data = page + (bkpb->hole_offset + bkpb->hole_length); + rdt->len = BLCKSZ - (bkpb->hole_offset + bkpb->hole_length); + write_len += rdt->len; + rdt->next = NULL; + } + } + + /* + * If we backed up any full blocks and online backup is not in progress, + * mark the backup blocks as removable. This allows the WAL archiver to + * know whether it is safe to compress archived WAL data by transforming + * full-block records into the non-full-block format. + * + * Note: we could just set the flag whenever !forcePageWrites, but + * defining it like this leaves the info bit free for some potential other + * use in records without any backup blocks. + */ + if ((info & XLR_BKP_BLOCK_MASK) && !Insert->forcePageWrites) + info |= XLR_BKP_REMOVABLE; + + /* + * If there isn't enough space on the current XLOG page for a record + * header, advance to the next page (leaving the unused space as zeroes). + */ + updrqst = false; + freespace = INSERT_FREESPACE(Insert); + if (freespace < SizeOfXLogRecord) + { + updrqst = AdvanceXLInsertBuffer(false); + freespace = INSERT_FREESPACE(Insert); + } + + /* Compute record's XLOG location */ + curridx = Insert->curridx; + INSERT_RECPTR(RecPtr, Insert, curridx); + + /* + * If the record is an XLOG_SWITCH, and we are exactly at the start of a + * segment, we need not insert it (and don't want to because we'd like + * consecutive switch requests to be no-ops). Instead, make sure + * everything is written and flushed through the end of the prior segment, + * and return the prior segment's end address. + */ + if (isLogSwitch && + (RecPtr.xrecoff % XLogSegSize) == SizeOfXLogLongPHD) + { + /* We can release insert lock immediately */ + LWLockRelease(WALInsertLock); + + RecPtr.xrecoff -= SizeOfXLogLongPHD; + if (RecPtr.xrecoff == 0) + { + /* crossing a logid boundary */ + RecPtr.xlogid -= 1; + RecPtr.xrecoff = XLogFileSize; + } + + LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); + LogwrtResult = XLogCtl->Write.LogwrtResult; + if (!XLByteLE(RecPtr, LogwrtResult.Flush)) + { + XLogwrtRqst FlushRqst; + + FlushRqst.Write = RecPtr; + FlushRqst.Flush = RecPtr; + XLogWrite(FlushRqst, false, false); + } + LWLockRelease(WALWriteLock); + + END_CRIT_SECTION(); + + return RecPtr; + } + + /* Insert record header */ + + record = (XLogRecord *) Insert->currpos; + record->xl_prev = Insert->PrevRecord; + record->xl_xid = GetCurrentTransactionIdIfAny(); + record->xl_tot_len = SizeOfXLogRecord + write_len; + record->xl_len = len; /* doesn't include backup blocks */ + record->xl_info = info; + record->xl_rmid = rmid; + + /* Now we can finish computing the record's CRC */ + COMP_CRC32(rdata_crc, (char *) record + sizeof(pg_crc32), + SizeOfXLogRecord - sizeof(pg_crc32)); + FIN_CRC32(rdata_crc); + record->xl_crc = rdata_crc; + + #ifdef WAL_DEBUG + if (XLOG_DEBUG) + { + StringInfoData buf; + + initStringInfo(&buf); + appendStringInfo(&buf, "INSERT @ %X/%X: ", + RecPtr.xlogid, RecPtr.xrecoff); + xlog_outrec(&buf, record); + if (rdata->data != NULL) + { + appendStringInfo(&buf, " - "); + RmgrTable[record->xl_rmid].rm_desc(&buf, record->xl_info, rdata->data); + } + elog(LOG, "%s", buf.data); + pfree(buf.data); + } + #endif + + /* Record begin of record in appropriate places */ + ProcLastRecPtr = RecPtr; + Insert->PrevRecord = RecPtr; + + Insert->currpos += SizeOfXLogRecord; + freespace -= SizeOfXLogRecord; + + /* + * Append the data, including backup blocks if any + */ + while (write_len) + { + while (rdata->data == NULL) + rdata = rdata->next; + + if (freespace > 0) + { + if (rdata->len > freespace) + { + memcpy(Insert->currpos, rdata->data, freespace); + rdata->data += freespace; + rdata->len -= freespace; + write_len -= freespace; + } + else + { + memcpy(Insert->currpos, rdata->data, rdata->len); + freespace -= rdata->len; + write_len -= rdata->len; + Insert->currpos += rdata->len; + rdata = rdata->next; + continue; + } + } + + /* Use next buffer */ + updrqst = AdvanceXLInsertBuffer(false); + curridx = Insert->curridx; + /* Insert cont-record header */ + Insert->currpage->xlp_info |= XLP_FIRST_IS_CONTRECORD; + contrecord = (XLogContRecord *) Insert->currpos; + contrecord->xl_rem_len = write_len; + Insert->currpos += SizeOfXLogContRecord; + freespace = INSERT_FREESPACE(Insert); + } + + /* Ensure next record will be properly aligned */ + Insert->currpos = (char *) Insert->currpage + + MAXALIGN(Insert->currpos - (char *) Insert->currpage); + freespace = INSERT_FREESPACE(Insert); + + /* + * The recptr I return is the beginning of the *next* record. This will be + * stored as LSN for changed data pages... + */ + INSERT_RECPTR(RecPtr, Insert, curridx); + + /* + * If the record is an XLOG_SWITCH, we must now write and flush all the + * existing data, and then forcibly advance to the start of the next + * segment. It's not good to do this I/O while holding the insert lock, + * but there seems too much risk of confusion if we try to release the + * lock sooner. Fortunately xlog switch needn't be a high-performance + * operation anyway... + */ + if (isLogSwitch) + { + XLogCtlWrite *Write = &XLogCtl->Write; + XLogwrtRqst FlushRqst; + XLogRecPtr OldSegEnd; + + TRACE_POSTGRESQL_XLOG_SWITCH(); + + LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); + + /* + * Flush through the end of the page containing XLOG_SWITCH, and + * perform end-of-segment actions (eg, notifying archiver). + */ + WriteRqst = XLogCtl->xlblocks[curridx]; + FlushRqst.Write = WriteRqst; + FlushRqst.Flush = WriteRqst; + XLogWrite(FlushRqst, false, true); + + /* Set up the next buffer as first page of next segment */ + /* Note: AdvanceXLInsertBuffer cannot need to do I/O here */ + (void) AdvanceXLInsertBuffer(true); + + /* There should be no unwritten data */ + curridx = Insert->curridx; + Assert(curridx == Write->curridx); + + /* Compute end address of old segment */ + OldSegEnd = XLogCtl->xlblocks[curridx]; + OldSegEnd.xrecoff -= XLOG_BLCKSZ; + if (OldSegEnd.xrecoff == 0) + { + /* crossing a logid boundary */ + OldSegEnd.xlogid -= 1; + OldSegEnd.xrecoff = XLogFileSize; + } + + /* Make it look like we've written and synced all of old segment */ + LogwrtResult.Write = OldSegEnd; + LogwrtResult.Flush = OldSegEnd; + + /* + * Update shared-memory status --- this code should match XLogWrite + */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + xlogctl->LogwrtResult = LogwrtResult; + if (XLByteLT(xlogctl->LogwrtRqst.Write, LogwrtResult.Write)) + xlogctl->LogwrtRqst.Write = LogwrtResult.Write; + if (XLByteLT(xlogctl->LogwrtRqst.Flush, LogwrtResult.Flush)) + xlogctl->LogwrtRqst.Flush = LogwrtResult.Flush; + SpinLockRelease(&xlogctl->info_lck); + } + + Write->LogwrtResult = LogwrtResult; + + LWLockRelease(WALWriteLock); + + updrqst = false; /* done already */ + } + else + { + /* normal case, ie not xlog switch */ + + /* Need to update shared LogwrtRqst if some block was filled up */ + if (freespace < SizeOfXLogRecord) + { + /* curridx is filled and available for writing out */ + updrqst = true; + } + else + { + /* if updrqst already set, write through end of previous buf */ + curridx = PrevBufIdx(curridx); + } + WriteRqst = XLogCtl->xlblocks[curridx]; + } + + LWLockRelease(WALInsertLock); + + if (updrqst) + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + /* advance global request to include new block(s) */ + if (XLByteLT(xlogctl->LogwrtRqst.Write, WriteRqst)) + xlogctl->LogwrtRqst.Write = WriteRqst; + /* update local result copy while I have the chance */ + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease(&xlogctl->info_lck); + } + + XactLastRecEnd = RecPtr; + + END_CRIT_SECTION(); + + return RecPtr; + } + + /* + * Determine whether the buffer referenced by an XLogRecData item has to + * be backed up, and if so fill a BkpBlock struct for it. In any case + * save the buffer's LSN at *lsn. + */ + static bool + XLogCheckBuffer(XLogRecData *rdata, bool doPageWrites, + XLogRecPtr *lsn, BkpBlock *bkpb) + { + Page page; + + page = BufferGetPage(rdata->buffer); + + /* + * XXX We assume page LSN is first data on *every* page that can be passed + * to XLogInsert, whether it otherwise has the standard page layout or + * not. + */ + *lsn = PageGetLSN(page); + + if (doPageWrites && + XLByteLE(PageGetLSN(page), RedoRecPtr)) + { + /* + * The page needs to be backed up, so set up *bkpb + */ + BufferGetTag(rdata->buffer, &bkpb->node, &bkpb->fork, &bkpb->block); + + if (rdata->buffer_std) + { + /* Assume we can omit data between pd_lower and pd_upper */ + uint16 lower = ((PageHeader) page)->pd_lower; + uint16 upper = ((PageHeader) page)->pd_upper; + + if (lower >= SizeOfPageHeaderData && + upper > lower && + upper <= BLCKSZ) + { + bkpb->hole_offset = lower; + bkpb->hole_length = upper - lower; + } + else + { + /* No "hole" to compress out */ + bkpb->hole_offset = 0; + bkpb->hole_length = 0; + } + } + else + { + /* Not a standard page header, don't try to eliminate "hole" */ + bkpb->hole_offset = 0; + bkpb->hole_length = 0; + } + + return true; /* buffer requires backup */ + } + + return false; /* buffer does not need to be backed up */ + } + + /* + * XLogArchiveNotify + * + * Create an archive notification file + * + * The name of the notification file is the message that will be picked up + * by the archiver, e.g. we write 0000000100000001000000C6.ready + * and the archiver then knows to archive XLOGDIR/0000000100000001000000C6, + * then when complete, rename it to 0000000100000001000000C6.done + */ + static void + XLogArchiveNotify(const char *xlog) + { + char archiveStatusPath[MAXPGPATH]; + FILE *fd; + + /* insert an otherwise empty file called .ready */ + StatusFilePath(archiveStatusPath, xlog, ".ready"); + fd = AllocateFile(archiveStatusPath, "w"); + if (fd == NULL) + { + ereport(LOG, + (errcode_for_file_access(), + errmsg("could not create archive status file \"%s\": %m", + archiveStatusPath))); + return; + } + if (FreeFile(fd)) + { + ereport(LOG, + (errcode_for_file_access(), + errmsg("could not write archive status file \"%s\": %m", + archiveStatusPath))); + return; + } + + /* Notify archiver that it's got something to do */ + if (IsUnderPostmaster) + SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER); + } + + /* + * Convenience routine to notify using log/seg representation of filename + */ + static void + XLogArchiveNotifySeg(uint32 log, uint32 seg) + { + char xlog[MAXFNAMELEN]; + + XLogFileName(xlog, ThisTimeLineID, log, seg); + XLogArchiveNotify(xlog); + } + + /* + * XLogArchiveCheckDone + * + * This is called when we are ready to delete or recycle an old XLOG segment + * file or backup history file. If it is okay to delete it then return true. + * If it is not time to delete it, make sure a .ready file exists, and return + * false. + * + * If .done exists, then return true; else if .ready exists, + * then return false; else create .ready and return false. + * + * The reason we do things this way is so that if the original attempt to + * create .ready fails, we'll retry during subsequent checkpoints. + */ + static bool + XLogArchiveCheckDone(const char *xlog) + { + char archiveStatusPath[MAXPGPATH]; + struct stat stat_buf; + + /* Always deletable if archiving is off */ + if (!XLogArchivingActive()) + return true; + + /* First check for .done --- this means archiver is done with it */ + StatusFilePath(archiveStatusPath, xlog, ".done"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return true; + + /* check for .ready --- this means archiver is still busy with it */ + StatusFilePath(archiveStatusPath, xlog, ".ready"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return false; + + /* Race condition --- maybe archiver just finished, so recheck */ + StatusFilePath(archiveStatusPath, xlog, ".done"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return true; + + /* Retry creation of the .ready file */ + XLogArchiveNotify(xlog); + return false; + } + + /* + * XLogArchiveIsBusy + * + * Check to see if an XLOG segment file is still unarchived. + * This is almost but not quite the inverse of XLogArchiveCheckDone: in + * the first place we aren't chartered to recreate the .ready file, and + * in the second place we should consider that if the file is already gone + * then it's not busy. (This check is needed to handle the race condition + * that a checkpoint already deleted the no-longer-needed file.) + */ + static bool + XLogArchiveIsBusy(const char *xlog) + { + char archiveStatusPath[MAXPGPATH]; + struct stat stat_buf; + + /* First check for .done --- this means archiver is done with it */ + StatusFilePath(archiveStatusPath, xlog, ".done"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return false; + + /* check for .ready --- this means archiver is still busy with it */ + StatusFilePath(archiveStatusPath, xlog, ".ready"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return true; + + /* Race condition --- maybe archiver just finished, so recheck */ + StatusFilePath(archiveStatusPath, xlog, ".done"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return false; + + /* + * Check to see if the WAL file has been removed by checkpoint, + * which implies it has already been archived, and explains why we + * can't see a status file for it. + */ + snprintf(archiveStatusPath, MAXPGPATH, XLOGDIR "/%s", xlog); + if (stat(archiveStatusPath, &stat_buf) != 0 && + errno == ENOENT) + return false; + + return true; + } + + /* + * XLogArchiveCleanup + * + * Cleanup archive notification file(s) for a particular xlog segment + */ + static void + XLogArchiveCleanup(const char *xlog) + { + char archiveStatusPath[MAXPGPATH]; + + /* Remove the .done file */ + StatusFilePath(archiveStatusPath, xlog, ".done"); + unlink(archiveStatusPath); + /* should we complain about failure? */ + + /* Remove the .ready file if present --- normally it shouldn't be */ + StatusFilePath(archiveStatusPath, xlog, ".ready"); + unlink(archiveStatusPath); + /* should we complain about failure? */ + } + + /* + * Advance the Insert state to the next buffer page, writing out the next + * buffer if it still contains unwritten data. + * + * If new_segment is TRUE then we set up the next buffer page as the first + * page of the next xlog segment file, possibly but not usually the next + * consecutive file page. + * + * The global LogwrtRqst.Write pointer needs to be advanced to include the + * just-filled page. If we can do this for free (without an extra lock), + * we do so here. Otherwise the caller must do it. We return TRUE if the + * request update still needs to be done, FALSE if we did it internally. + * + * Must be called with WALInsertLock held. + */ + static bool + AdvanceXLInsertBuffer(bool new_segment) + { + XLogCtlInsert *Insert = &XLogCtl->Insert; + XLogCtlWrite *Write = &XLogCtl->Write; + int nextidx = NextBufIdx(Insert->curridx); + bool update_needed = true; + XLogRecPtr OldPageRqstPtr; + XLogwrtRqst WriteRqst; + XLogRecPtr NewPageEndPtr; + XLogPageHeader NewPage; + + /* Use Insert->LogwrtResult copy if it's more fresh */ + if (XLByteLT(LogwrtResult.Write, Insert->LogwrtResult.Write)) + LogwrtResult = Insert->LogwrtResult; + + /* + * Get ending-offset of the buffer page we need to replace (this may be + * zero if the buffer hasn't been used yet). Fall through if it's already + * written out. + */ + OldPageRqstPtr = XLogCtl->xlblocks[nextidx]; + if (!XLByteLE(OldPageRqstPtr, LogwrtResult.Write)) + { + /* nope, got work to do... */ + XLogRecPtr FinishedPageRqstPtr; + + FinishedPageRqstPtr = XLogCtl->xlblocks[Insert->curridx]; + + /* Before waiting, get info_lck and update LogwrtResult */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + if (XLByteLT(xlogctl->LogwrtRqst.Write, FinishedPageRqstPtr)) + xlogctl->LogwrtRqst.Write = FinishedPageRqstPtr; + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease(&xlogctl->info_lck); + } + + update_needed = false; /* Did the shared-request update */ + + if (XLByteLE(OldPageRqstPtr, LogwrtResult.Write)) + { + /* OK, someone wrote it already */ + Insert->LogwrtResult = LogwrtResult; + } + else + { + /* Must acquire write lock */ + LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); + LogwrtResult = Write->LogwrtResult; + if (XLByteLE(OldPageRqstPtr, LogwrtResult.Write)) + { + /* OK, someone wrote it already */ + LWLockRelease(WALWriteLock); + Insert->LogwrtResult = LogwrtResult; + } + else + { + /* + * Have to write buffers while holding insert lock. This is + * not good, so only write as much as we absolutely must. + */ + TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_START(); + WriteRqst.Write = OldPageRqstPtr; + WriteRqst.Flush.xlogid = 0; + WriteRqst.Flush.xrecoff = 0; + XLogWrite(WriteRqst, false, false); + LWLockRelease(WALWriteLock); + Insert->LogwrtResult = LogwrtResult; + TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE(); + } + } + } + + /* + * Now the next buffer slot is free and we can set it up to be the next + * output page. + */ + NewPageEndPtr = XLogCtl->xlblocks[Insert->curridx]; + + if (new_segment) + { + /* force it to a segment start point */ + NewPageEndPtr.xrecoff += XLogSegSize - 1; + NewPageEndPtr.xrecoff -= NewPageEndPtr.xrecoff % XLogSegSize; + } + + if (NewPageEndPtr.xrecoff >= XLogFileSize) + { + /* crossing a logid boundary */ + NewPageEndPtr.xlogid += 1; + NewPageEndPtr.xrecoff = XLOG_BLCKSZ; + } + else + NewPageEndPtr.xrecoff += XLOG_BLCKSZ; + XLogCtl->xlblocks[nextidx] = NewPageEndPtr; + NewPage = (XLogPageHeader) (XLogCtl->pages + nextidx * (Size) XLOG_BLCKSZ); + + Insert->curridx = nextidx; + Insert->currpage = NewPage; + + Insert->currpos = ((char *) NewPage) +SizeOfXLogShortPHD; + + /* + * Be sure to re-zero the buffer so that bytes beyond what we've written + * will look like zeroes and not valid XLOG records... + */ + MemSet((char *) NewPage, 0, XLOG_BLCKSZ); + + /* + * Fill the new page's header + */ + NewPage ->xlp_magic = XLOG_PAGE_MAGIC; + + /* NewPage->xlp_info = 0; */ /* done by memset */ + NewPage ->xlp_tli = ThisTimeLineID; + NewPage ->xlp_pageaddr.xlogid = NewPageEndPtr.xlogid; + NewPage ->xlp_pageaddr.xrecoff = NewPageEndPtr.xrecoff - XLOG_BLCKSZ; + + /* + * If first page of an XLOG segment file, make it a long header. + */ + if ((NewPage->xlp_pageaddr.xrecoff % XLogSegSize) == 0) + { + XLogLongPageHeader NewLongPage = (XLogLongPageHeader) NewPage; + + NewLongPage->xlp_sysid = ControlFile->system_identifier; + NewLongPage->xlp_seg_size = XLogSegSize; + NewLongPage->xlp_xlog_blcksz = XLOG_BLCKSZ; + NewPage ->xlp_info |= XLP_LONG_HEADER; + + Insert->currpos = ((char *) NewPage) +SizeOfXLogLongPHD; + } + + return update_needed; + } + + /* + * Check whether we've consumed enough xlog space that a checkpoint is needed. + * + * Caller must have just finished filling the open log file (so that + * openLogId/openLogSeg are valid). We measure the distance from RedoRecPtr + * to the open log file and see if that exceeds CheckPointSegments. + * + * Note: it is caller's responsibility that RedoRecPtr is up-to-date. + */ + static bool + XLogCheckpointNeeded(void) + { + /* + * A straight computation of segment number could overflow 32 bits. Rather + * than assuming we have working 64-bit arithmetic, we compare the + * highest-order bits separately, and force a checkpoint immediately when + * they change. + */ + uint32 old_segno, + new_segno; + uint32 old_highbits, + new_highbits; + + old_segno = (RedoRecPtr.xlogid % XLogSegSize) * XLogSegsPerFile + + (RedoRecPtr.xrecoff / XLogSegSize); + old_highbits = RedoRecPtr.xlogid / XLogSegSize; + new_segno = (openLogId % XLogSegSize) * XLogSegsPerFile + openLogSeg; + new_highbits = openLogId / XLogSegSize; + if (new_highbits != old_highbits || + new_segno >= old_segno + (uint32) (CheckPointSegments - 1)) + return true; + return false; + } + + /* + * Write and/or fsync the log at least as far as WriteRqst indicates. + * + * If flexible == TRUE, we don't have to write as far as WriteRqst, but + * may stop at any convenient boundary (such as a cache or logfile boundary). + * This option allows us to avoid uselessly issuing multiple writes when a + * single one would do. + * + * If xlog_switch == TRUE, we are intending an xlog segment switch, so + * perform end-of-segment actions after writing the last page, even if + * it's not physically the end of its segment. (NB: this will work properly + * only if caller specifies WriteRqst == page-end and flexible == false, + * and there is some data to write.) + * + * Must be called with WALWriteLock held. + */ + static void + XLogWrite(XLogwrtRqst WriteRqst, bool flexible, bool xlog_switch) + { + XLogCtlWrite *Write = &XLogCtl->Write; + bool ispartialpage; + bool last_iteration; + bool finishing_seg; + bool use_existent; + int curridx; + int npages; + int startidx; + uint32 startoffset; + + /* We should always be inside a critical section here */ + Assert(CritSectionCount > 0); + + /* + * Update local LogwrtResult (caller probably did this already, but...) + */ + LogwrtResult = Write->LogwrtResult; + + /* + * Since successive pages in the xlog cache are consecutively allocated, + * we can usually gather multiple pages together and issue just one + * write() call. npages is the number of pages we have determined can be + * written together; startidx is the cache block index of the first one, + * and startoffset is the file offset at which it should go. The latter + * two variables are only valid when npages > 0, but we must initialize + * all of them to keep the compiler quiet. + */ + npages = 0; + startidx = 0; + startoffset = 0; + + /* + * Within the loop, curridx is the cache block index of the page to + * consider writing. We advance Write->curridx only after successfully + * writing pages. (Right now, this refinement is useless since we are + * going to PANIC if any error occurs anyway; but someday it may come in + * useful.) + */ + curridx = Write->curridx; + + while (XLByteLT(LogwrtResult.Write, WriteRqst.Write)) + { + /* + * Make sure we're not ahead of the insert process. This could happen + * if we're passed a bogus WriteRqst.Write that is past the end of the + * last page that's been initialized by AdvanceXLInsertBuffer. + */ + if (!XLByteLT(LogwrtResult.Write, XLogCtl->xlblocks[curridx])) + elog(PANIC, "xlog write request %X/%X is past end of log %X/%X", + LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff, + XLogCtl->xlblocks[curridx].xlogid, + XLogCtl->xlblocks[curridx].xrecoff); + + /* Advance LogwrtResult.Write to end of current buffer page */ + LogwrtResult.Write = XLogCtl->xlblocks[curridx]; + ispartialpage = XLByteLT(WriteRqst.Write, LogwrtResult.Write); + + if (!XLByteInPrevSeg(LogwrtResult.Write, openLogId, openLogSeg)) + { + /* + * Switch to new logfile segment. We cannot have any pending + * pages here (since we dump what we have at segment end). + */ + Assert(npages == 0); + if (openLogFile >= 0) + XLogFileClose(); + XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg); + + /* create/use new log file */ + use_existent = true; + openLogFile = XLogFileInit(openLogId, openLogSeg, + &use_existent, true); + openLogOff = 0; + } + + /* Make sure we have the current logfile open */ + if (openLogFile < 0) + { + XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg); + openLogFile = XLogFileOpen(openLogId, openLogSeg); + openLogOff = 0; + } + + /* Add current page to the set of pending pages-to-dump */ + if (npages == 0) + { + /* first of group */ + startidx = curridx; + startoffset = (LogwrtResult.Write.xrecoff - XLOG_BLCKSZ) % XLogSegSize; + } + npages++; + + /* + * Dump the set if this will be the last loop iteration, or if we are + * at the last page of the cache area (since the next page won't be + * contiguous in memory), or if we are at the end of the logfile + * segment. + */ + last_iteration = !XLByteLT(LogwrtResult.Write, WriteRqst.Write); + + finishing_seg = !ispartialpage && + (startoffset + npages * XLOG_BLCKSZ) >= XLogSegSize; + + if (last_iteration || + curridx == XLogCtl->XLogCacheBlck || + finishing_seg) + { + char *from; + Size nbytes; + + /* Need to seek in the file? */ + if (openLogOff != startoffset) + { + if (lseek(openLogFile, (off_t) startoffset, SEEK_SET) < 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not seek in log file %u, " + "segment %u to offset %u: %m", + openLogId, openLogSeg, startoffset))); + openLogOff = startoffset; + } + + /* OK to write the page(s) */ + from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ; + nbytes = npages * (Size) XLOG_BLCKSZ; + errno = 0; + if (write(openLogFile, from, nbytes) != nbytes) + { + /* if write didn't set errno, assume no disk space */ + if (errno == 0) + errno = ENOSPC; + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not write to log file %u, segment %u " + "at offset %u, length %lu: %m", + openLogId, openLogSeg, + openLogOff, (unsigned long) nbytes))); + } + + /* Update state for write */ + openLogOff += nbytes; + Write->curridx = ispartialpage ? curridx : NextBufIdx(curridx); + npages = 0; + + /* + * If we just wrote the whole last page of a logfile segment, + * fsync the segment immediately. This avoids having to go back + * and re-open prior segments when an fsync request comes along + * later. Doing it here ensures that one and only one backend will + * perform this fsync. + * + * We also do this if this is the last page written for an xlog + * switch. + * + * This is also the right place to notify the Archiver that the + * segment is ready to copy to archival storage, and to update the + * timer for archive_timeout, and to signal for a checkpoint if + * too many logfile segments have been used since the last + * checkpoint. + */ + if (finishing_seg || (xlog_switch && last_iteration)) + { + issue_xlog_fsync(); + LogwrtResult.Flush = LogwrtResult.Write; /* end of page */ + + if (XLogArchivingActive()) + XLogArchiveNotifySeg(openLogId, openLogSeg); + + Write->lastSegSwitchTime = (pg_time_t) time(NULL); + + /* + * Signal bgwriter to start a checkpoint if we've consumed too + * much xlog since the last one. For speed, we first check + * using the local copy of RedoRecPtr, which might be out of + * date; if it looks like a checkpoint is needed, forcibly + * update RedoRecPtr and recheck. + */ + if (IsUnderPostmaster && + XLogCheckpointNeeded()) + { + (void) GetRedoRecPtr(); + if (XLogCheckpointNeeded()) + RequestCheckpoint(CHECKPOINT_CAUSE_XLOG); + } + } + } + + if (ispartialpage) + { + /* Only asked to write a partial page */ + LogwrtResult.Write = WriteRqst.Write; + break; + } + curridx = NextBufIdx(curridx); + + /* If flexible, break out of loop as soon as we wrote something */ + if (flexible && npages == 0) + break; + } + + Assert(npages == 0); + Assert(curridx == Write->curridx); + + /* + * If asked to flush, do so + */ + if (XLByteLT(LogwrtResult.Flush, WriteRqst.Flush) && + XLByteLT(LogwrtResult.Flush, LogwrtResult.Write)) + { + /* + * Could get here without iterating above loop, in which case we might + * have no open file or the wrong one. However, we do not need to + * fsync more than one file. + */ + if (sync_method != SYNC_METHOD_OPEN && + sync_method != SYNC_METHOD_OPEN_DSYNC) + { + if (openLogFile >= 0 && + !XLByteInPrevSeg(LogwrtResult.Write, openLogId, openLogSeg)) + XLogFileClose(); + if (openLogFile < 0) + { + XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg); + openLogFile = XLogFileOpen(openLogId, openLogSeg); + openLogOff = 0; + } + issue_xlog_fsync(); + } + LogwrtResult.Flush = LogwrtResult.Write; + } + + /* + * Update shared-memory status + * + * We make sure that the shared 'request' values do not fall behind the + * 'result' values. This is not absolutely essential, but it saves some + * code in a couple of places. + */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + xlogctl->LogwrtResult = LogwrtResult; + if (XLByteLT(xlogctl->LogwrtRqst.Write, LogwrtResult.Write)) + xlogctl->LogwrtRqst.Write = LogwrtResult.Write; + if (XLByteLT(xlogctl->LogwrtRqst.Flush, LogwrtResult.Flush)) + xlogctl->LogwrtRqst.Flush = LogwrtResult.Flush; + SpinLockRelease(&xlogctl->info_lck); + } + + Write->LogwrtResult = LogwrtResult; + } + + /* + * Record the LSN for an asynchronous transaction commit. + * (This should not be called for aborts, nor for synchronous commits.) + */ + void + XLogSetAsyncCommitLSN(XLogRecPtr asyncCommitLSN) + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + if (XLByteLT(xlogctl->asyncCommitLSN, asyncCommitLSN)) + xlogctl->asyncCommitLSN = asyncCommitLSN; + SpinLockRelease(&xlogctl->info_lck); + } + + /* + * Ensure that all XLOG data through the given position is flushed to disk. + * + * NOTE: this differs from XLogWrite mainly in that the WALWriteLock is not + * already held, and we try to avoid acquiring it if possible. + */ + void + XLogFlush(XLogRecPtr record) + { + XLogRecPtr WriteRqstPtr; + XLogwrtRqst WriteRqst; + + /* Disabled during REDO */ + if (InRedo) + return; + + /* Quick exit if already known flushed */ + if (XLByteLE(record, LogwrtResult.Flush)) + return; + + #ifdef WAL_DEBUG + if (XLOG_DEBUG) + elog(LOG, "xlog flush request %X/%X; write %X/%X; flush %X/%X", + record.xlogid, record.xrecoff, + LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff, + LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff); + #endif + + START_CRIT_SECTION(); + + /* + * Since fsync is usually a horribly expensive operation, we try to + * piggyback as much data as we can on each fsync: if we see any more data + * entered into the xlog buffer, we'll write and fsync that too, so that + * the final value of LogwrtResult.Flush is as large as possible. This + * gives us some chance of avoiding another fsync immediately after. + */ + + /* initialize to given target; may increase below */ + WriteRqstPtr = record; + + /* read LogwrtResult and update local state */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + if (XLByteLT(WriteRqstPtr, xlogctl->LogwrtRqst.Write)) + WriteRqstPtr = xlogctl->LogwrtRqst.Write; + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease(&xlogctl->info_lck); + } + + /* done already? */ + if (!XLByteLE(record, LogwrtResult.Flush)) + { + /* now wait for the write lock */ + LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); + LogwrtResult = XLogCtl->Write.LogwrtResult; + if (!XLByteLE(record, LogwrtResult.Flush)) + { + /* try to write/flush later additions to XLOG as well */ + if (LWLockConditionalAcquire(WALInsertLock, LW_EXCLUSIVE)) + { + XLogCtlInsert *Insert = &XLogCtl->Insert; + uint32 freespace = INSERT_FREESPACE(Insert); + + if (freespace < SizeOfXLogRecord) /* buffer is full */ + WriteRqstPtr = XLogCtl->xlblocks[Insert->curridx]; + else + { + WriteRqstPtr = XLogCtl->xlblocks[Insert->curridx]; + WriteRqstPtr.xrecoff -= freespace; + } + LWLockRelease(WALInsertLock); + WriteRqst.Write = WriteRqstPtr; + WriteRqst.Flush = WriteRqstPtr; + } + else + { + WriteRqst.Write = WriteRqstPtr; + WriteRqst.Flush = record; + } + XLogWrite(WriteRqst, false, false); + } + LWLockRelease(WALWriteLock); + } + + END_CRIT_SECTION(); + + /* + * If we still haven't flushed to the request point then we have a + * problem; most likely, the requested flush point is past end of XLOG. + * This has been seen to occur when a disk page has a corrupted LSN. + * + * Formerly we treated this as a PANIC condition, but that hurts the + * system's robustness rather than helping it: we do not want to take down + * the whole system due to corruption on one data page. In particular, if + * the bad page is encountered again during recovery then we would be + * unable to restart the database at all! (This scenario has actually + * happened in the field several times with 7.1 releases. Note that we + * cannot get here while InRedo is true, but if the bad page is brought in + * and marked dirty during recovery then CreateCheckPoint will try to + * flush it at the end of recovery.) + * + * The current approach is to ERROR under normal conditions, but only + * WARNING during recovery, so that the system can be brought up even if + * there's a corrupt LSN. Note that for calls from xact.c, the ERROR will + * be promoted to PANIC since xact.c calls this routine inside a critical + * section. However, calls from bufmgr.c are not within critical sections + * and so we will not force a restart for a bad LSN on a data page. + */ + if (XLByteLT(LogwrtResult.Flush, record)) + elog(InRecovery ? WARNING : ERROR, + "xlog flush request %X/%X is not satisfied --- flushed only to %X/%X", + record.xlogid, record.xrecoff, + LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff); + } + + /* + * Flush xlog, but without specifying exactly where to flush to. + * + * We normally flush only completed blocks; but if there is nothing to do on + * that basis, we check for unflushed async commits in the current incomplete + * block, and flush through the latest one of those. Thus, if async commits + * are not being used, we will flush complete blocks only. We can guarantee + * that async commits reach disk after at most three cycles; normally only + * one or two. (We allow XLogWrite to write "flexibly", meaning it can stop + * at the end of the buffer ring; this makes a difference only with very high + * load or long wal_writer_delay, but imposes one extra cycle for the worst + * case for async commits.) + * + * This routine is invoked periodically by the background walwriter process. + */ + void + XLogBackgroundFlush(void) + { + XLogRecPtr WriteRqstPtr; + bool flexible = true; + + /* read LogwrtResult and update local state */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + LogwrtResult = xlogctl->LogwrtResult; + WriteRqstPtr = xlogctl->LogwrtRqst.Write; + SpinLockRelease(&xlogctl->info_lck); + } + + /* back off to last completed page boundary */ + WriteRqstPtr.xrecoff -= WriteRqstPtr.xrecoff % XLOG_BLCKSZ; + + /* if we have already flushed that far, consider async commit records */ + if (XLByteLE(WriteRqstPtr, LogwrtResult.Flush)) + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + WriteRqstPtr = xlogctl->asyncCommitLSN; + SpinLockRelease(&xlogctl->info_lck); + flexible = false; /* ensure it all gets written */ + } + + /* Done if already known flushed */ + if (XLByteLE(WriteRqstPtr, LogwrtResult.Flush)) + return; + + #ifdef WAL_DEBUG + if (XLOG_DEBUG) + elog(LOG, "xlog bg flush request %X/%X; write %X/%X; flush %X/%X", + WriteRqstPtr.xlogid, WriteRqstPtr.xrecoff, + LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff, + LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff); + #endif + + START_CRIT_SECTION(); + + /* now wait for the write lock */ + LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); + LogwrtResult = XLogCtl->Write.LogwrtResult; + if (!XLByteLE(WriteRqstPtr, LogwrtResult.Flush)) + { + XLogwrtRqst WriteRqst; + + WriteRqst.Write = WriteRqstPtr; + WriteRqst.Flush = WriteRqstPtr; + XLogWrite(WriteRqst, flexible, false); + } + LWLockRelease(WALWriteLock); + + END_CRIT_SECTION(); + } + + /* + * Flush any previous asynchronously-committed transactions' commit records. + * + * NOTE: it is unwise to assume that this provides any strong guarantees. + * In particular, because of the inexact LSN bookkeeping used by clog.c, + * we cannot assume that hint bits will be settable for these transactions. + */ + void + XLogAsyncCommitFlush(void) + { + XLogRecPtr WriteRqstPtr; + + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + WriteRqstPtr = xlogctl->asyncCommitLSN; + SpinLockRelease(&xlogctl->info_lck); + + XLogFlush(WriteRqstPtr); + } + + /* + * Test whether XLOG data has been flushed up to (at least) the given position. + * + * Returns true if a flush is still needed. (It may be that someone else + * is already in process of flushing that far, however.) + */ + bool + XLogNeedsFlush(XLogRecPtr record) + { + /* Quick exit if already known flushed */ + if (XLByteLE(record, LogwrtResult.Flush)) + return false; + + /* read LogwrtResult and update local state */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease(&xlogctl->info_lck); + } + + /* check again */ + if (XLByteLE(record, LogwrtResult.Flush)) + return false; + + return true; + } + + /* + * Create a new XLOG file segment, or open a pre-existing one. + * + * log, seg: identify segment to be created/opened. + * + * *use_existent: if TRUE, OK to use a pre-existing file (else, any + * pre-existing file will be deleted). On return, TRUE if a pre-existing + * file was used. + * + * use_lock: if TRUE, acquire ControlFileLock while moving file into + * place. This should be TRUE except during bootstrap log creation. The + * caller must *not* hold the lock at call. + * + * Returns FD of opened file. + * + * Note: errors here are ERROR not PANIC because we might or might not be + * inside a critical section (eg, during checkpoint there is no reason to + * take down the system on failure). They will promote to PANIC if we are + * in a critical section. + */ + static int + XLogFileInit(uint32 log, uint32 seg, + bool *use_existent, bool use_lock) + { + char path[MAXPGPATH]; + char tmppath[MAXPGPATH]; + char *zbuffer; + uint32 installed_log; + uint32 installed_seg; + int max_advance; + int fd; + int nbytes; + + XLogFilePath(path, ThisTimeLineID, log, seg); + + /* + * Try to use existent file (checkpoint maker may have created it already) + */ + if (*use_existent) + { + fd = BasicOpenFile(path, O_RDWR | PG_BINARY | get_sync_bit(sync_method), + S_IRUSR | S_IWUSR); + if (fd < 0) + { + if (errno != ENOENT) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open file \"%s\" (log file %u, segment %u): %m", + path, log, seg))); + } + else + return fd; + } + + /* + * Initialize an empty (all zeroes) segment. NOTE: it is possible that + * another process is doing the same thing. If so, we will end up + * pre-creating an extra log segment. That seems OK, and better than + * holding the lock throughout this lengthy process. + */ + elog(DEBUG2, "creating and filling new WAL file"); + + snprintf(tmppath, MAXPGPATH, XLOGDIR "/xlogtemp.%d", (int) getpid()); + + unlink(tmppath); + + /* do not use get_sync_bit() here --- want to fsync only at end of fill */ + fd = BasicOpenFile(tmppath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not create file \"%s\": %m", tmppath))); + + /* + * Zero-fill the file. We have to do this the hard way to ensure that all + * the file space has really been allocated --- on platforms that allow + * "holes" in files, just seeking to the end doesn't allocate intermediate + * space. This way, we know that we have all the space and (after the + * fsync below) that all the indirect blocks are down on disk. Therefore, + * fdatasync(2) or O_DSYNC will be sufficient to sync future writes to the + * log file. + * + * Note: palloc zbuffer, instead of just using a local char array, to + * ensure it is reasonably well-aligned; this may save a few cycles + * transferring data to the kernel. + */ + zbuffer = (char *) palloc0(XLOG_BLCKSZ); + for (nbytes = 0; nbytes < XLogSegSize; nbytes += XLOG_BLCKSZ) + { + errno = 0; + if ((int) write(fd, zbuffer, XLOG_BLCKSZ) != (int) XLOG_BLCKSZ) + { + int save_errno = errno; + + /* + * If we fail to make the file, delete it to release disk space + */ + unlink(tmppath); + /* if write didn't set errno, assume problem is no disk space */ + errno = save_errno ? save_errno : ENOSPC; + + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write to file \"%s\": %m", tmppath))); + } + } + pfree(zbuffer); + + if (pg_fsync(fd) != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not fsync file \"%s\": %m", tmppath))); + + if (close(fd)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not close file \"%s\": %m", tmppath))); + + /* + * Now move the segment into place with its final name. + * + * If caller didn't want to use a pre-existing file, get rid of any + * pre-existing file. Otherwise, cope with possibility that someone else + * has created the file while we were filling ours: if so, use ours to + * pre-create a future log segment. + */ + installed_log = log; + installed_seg = seg; + max_advance = XLOGfileslop; + if (!InstallXLogFileSegment(&installed_log, &installed_seg, tmppath, + *use_existent, &max_advance, + use_lock)) + { + /* No need for any more future segments... */ + unlink(tmppath); + } + + elog(DEBUG2, "done creating and filling new WAL file"); + + /* Set flag to tell caller there was no existent file */ + *use_existent = false; + + /* Now open original target segment (might not be file I just made) */ + fd = BasicOpenFile(path, O_RDWR | PG_BINARY | get_sync_bit(sync_method), + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open file \"%s\" (log file %u, segment %u): %m", + path, log, seg))); + + return fd; + } + + /* + * Create a new XLOG file segment by copying a pre-existing one. + * + * log, seg: identify segment to be created. + * + * srcTLI, srclog, srcseg: identify segment to be copied (could be from + * a different timeline) + * + * Currently this is only used during recovery, and so there are no locking + * considerations. But we should be just as tense as XLogFileInit to avoid + * emplacing a bogus file. + */ + static void + XLogFileCopy(uint32 log, uint32 seg, + TimeLineID srcTLI, uint32 srclog, uint32 srcseg) + { + char path[MAXPGPATH]; + char tmppath[MAXPGPATH]; + char buffer[XLOG_BLCKSZ]; + int srcfd; + int fd; + int nbytes; + + /* + * Open the source file + */ + XLogFilePath(path, srcTLI, srclog, srcseg); + srcfd = BasicOpenFile(path, O_RDONLY | PG_BINARY, 0); + if (srcfd < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open file \"%s\": %m", path))); + + /* + * Copy into a temp file name. + */ + snprintf(tmppath, MAXPGPATH, XLOGDIR "/xlogtemp.%d", (int) getpid()); + + unlink(tmppath); + + /* do not use get_sync_bit() here --- want to fsync only at end of fill */ + fd = BasicOpenFile(tmppath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not create file \"%s\": %m", tmppath))); + + /* + * Do the data copying. + */ + for (nbytes = 0; nbytes < XLogSegSize; nbytes += sizeof(buffer)) + { + errno = 0; + if ((int) read(srcfd, buffer, sizeof(buffer)) != (int) sizeof(buffer)) + { + if (errno != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", path))); + else + ereport(ERROR, + (errmsg("not enough data in file \"%s\"", path))); + } + errno = 0; + if ((int) write(fd, buffer, sizeof(buffer)) != (int) sizeof(buffer)) + { + int save_errno = errno; + + /* + * If we fail to make the file, delete it to release disk space + */ + unlink(tmppath); + /* if write didn't set errno, assume problem is no disk space */ + errno = save_errno ? save_errno : ENOSPC; + + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write to file \"%s\": %m", tmppath))); + } + } + + if (pg_fsync(fd) != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not fsync file \"%s\": %m", tmppath))); + + if (close(fd)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not close file \"%s\": %m", tmppath))); + + close(srcfd); + + /* + * Now move the segment into place with its final name. + */ + if (!InstallXLogFileSegment(&log, &seg, tmppath, false, NULL, false)) + elog(ERROR, "InstallXLogFileSegment should not have failed"); + } + + /* + * Install a new XLOG segment file as a current or future log segment. + * + * This is used both to install a newly-created segment (which has a temp + * filename while it's being created) and to recycle an old segment. + * + * *log, *seg: identify segment to install as (or first possible target). + * When find_free is TRUE, these are modified on return to indicate the + * actual installation location or last segment searched. + * + * tmppath: initial name of file to install. It will be renamed into place. + * + * find_free: if TRUE, install the new segment at the first empty log/seg + * number at or after the passed numbers. If FALSE, install the new segment + * exactly where specified, deleting any existing segment file there. + * + * *max_advance: maximum number of log/seg slots to advance past the starting + * point. Fail if no free slot is found in this range. On return, reduced + * by the number of slots skipped over. (Irrelevant, and may be NULL, + * when find_free is FALSE.) + * + * use_lock: if TRUE, acquire ControlFileLock while moving file into + * place. This should be TRUE except during bootstrap log creation. The + * caller must *not* hold the lock at call. + * + * Returns TRUE if file installed, FALSE if not installed because of + * exceeding max_advance limit. On Windows, we also return FALSE if we + * can't rename the file into place because someone's got it open. + * (Any other kind of failure causes ereport().) + */ + static bool + InstallXLogFileSegment(uint32 *log, uint32 *seg, char *tmppath, + bool find_free, int *max_advance, + bool use_lock) + { + char path[MAXPGPATH]; + struct stat stat_buf; + + XLogFilePath(path, ThisTimeLineID, *log, *seg); + + /* + * We want to be sure that only one process does this at a time. + */ + if (use_lock) + LWLockAcquire(ControlFileLock, LW_EXCLUSIVE); + + if (!find_free) + { + /* Force installation: get rid of any pre-existing segment file */ + unlink(path); + } + else + { + /* Find a free slot to put it in */ + while (stat(path, &stat_buf) == 0) + { + if (*max_advance <= 0) + { + /* Failed to find a free slot within specified range */ + if (use_lock) + LWLockRelease(ControlFileLock); + return false; + } + NextLogSeg(*log, *seg); + (*max_advance)--; + XLogFilePath(path, ThisTimeLineID, *log, *seg); + } + } + + /* + * Prefer link() to rename() here just to be really sure that we don't + * overwrite an existing logfile. However, there shouldn't be one, so + * rename() is an acceptable substitute except for the truly paranoid. + */ + #if HAVE_WORKING_LINK + if (link(tmppath, path) < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not link file \"%s\" to \"%s\" (initialization of log file %u, segment %u): %m", + tmppath, path, *log, *seg))); + unlink(tmppath); + #else + if (rename(tmppath, path) < 0) + { + #ifdef WIN32 + #if !defined(__CYGWIN__) + if (GetLastError() == ERROR_ACCESS_DENIED) + #else + if (errno == EACCES) + #endif + { + if (use_lock) + LWLockRelease(ControlFileLock); + return false; + } + #endif /* WIN32 */ + + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\" (initialization of log file %u, segment %u): %m", + tmppath, path, *log, *seg))); + } + #endif + + if (use_lock) + LWLockRelease(ControlFileLock); + + return true; + } + + /* + * Open a pre-existing logfile segment for writing. + */ + static int + XLogFileOpen(uint32 log, uint32 seg) + { + char path[MAXPGPATH]; + int fd; + + XLogFilePath(path, ThisTimeLineID, log, seg); + + fd = BasicOpenFile(path, O_RDWR | PG_BINARY | get_sync_bit(sync_method), + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not open file \"%s\" (log file %u, segment %u): %m", + path, log, seg))); + + return fd; + } + + /* + * Open a logfile segment for reading (during recovery). + */ + static int + XLogFileRead(uint32 log, uint32 seg, int emode) + { + char path[MAXPGPATH]; + char xlogfname[MAXFNAMELEN]; + char activitymsg[MAXFNAMELEN + 16]; + ListCell *cell; + int fd; + + /* + * Loop looking for a suitable timeline ID: we might need to read any of + * the timelines listed in expectedTLIs. + * + * We expect curFileTLI on entry to be the TLI of the preceding file in + * sequence, or 0 if there was no predecessor. We do not allow curFileTLI + * to go backwards; this prevents us from picking up the wrong file when a + * parent timeline extends to higher segment numbers than the child we + * want to read. + */ + foreach(cell, expectedTLIs) + { + TimeLineID tli = (TimeLineID) lfirst_int(cell); + + if (tli < curFileTLI) + break; /* don't bother looking at too-old TLIs */ + + XLogFileName(xlogfname, tli, log, seg); + + if (InArchiveRecovery) + { + /* Report recovery progress in PS display */ + snprintf(activitymsg, sizeof(activitymsg), "waiting for %s", + xlogfname); + set_ps_display(activitymsg, false); + + restoredFromArchive = RestoreArchivedFile(path, xlogfname, + "RECOVERYXLOG", + XLogSegSize); + } + else + XLogFilePath(path, tli, log, seg); + + fd = BasicOpenFile(path, O_RDONLY | PG_BINARY, 0); + if (fd >= 0) + { + /* Success! */ + curFileTLI = tli; + + /* Report recovery progress in PS display */ + snprintf(activitymsg, sizeof(activitymsg), "recovering %s", + xlogfname); + set_ps_display(activitymsg, false); + + return fd; + } + if (errno != ENOENT) /* unexpected failure? */ + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not open file \"%s\" (log file %u, segment %u): %m", + path, log, seg))); + } + + /* Couldn't find it. For simplicity, complain about front timeline */ + XLogFilePath(path, recoveryTargetTLI, log, seg); + errno = ENOENT; + ereport(emode, + (errcode_for_file_access(), + errmsg("could not open file \"%s\" (log file %u, segment %u): %m", + path, log, seg))); + return -1; + } + + /* + * Close the current logfile segment for writing. + */ + static void + XLogFileClose(void) + { + Assert(openLogFile >= 0); + + /* + * WAL segment files will not be re-read in normal operation, so we advise + * the OS to release any cached pages. But do not do so if WAL archiving + * is active, because archiver process could use the cache to read the WAL + * segment. Also, don't bother with it if we are using O_DIRECT, since + * the kernel is presumably not caching in that case. + */ + #if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED) + if (!XLogArchivingActive() && + (get_sync_bit(sync_method) & PG_O_DIRECT) == 0) + (void) posix_fadvise(openLogFile, 0, 0, POSIX_FADV_DONTNEED); + #endif + + if (close(openLogFile)) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not close log file %u, segment %u: %m", + openLogId, openLogSeg))); + openLogFile = -1; + } + + /* + * Attempt to retrieve the specified file from off-line archival storage. + * If successful, fill "path" with its complete path (note that this will be + * a temp file name that doesn't follow the normal naming convention), and + * return TRUE. + * + * If not successful, fill "path" with the name of the normal on-line file + * (which may or may not actually exist, but we'll try to use it), and return + * FALSE. + * + * For fixed-size files, the caller may pass the expected size as an + * additional crosscheck on successful recovery. If the file size is not + * known, set expectedSize = 0. + */ + static bool + RestoreArchivedFile(char *path, const char *xlogfname, + const char *recovername, off_t expectedSize) + { + char xlogpath[MAXPGPATH]; + char xlogRestoreCmd[MAXPGPATH]; + char lastRestartPointFname[MAXPGPATH]; + char *dp; + char *endp; + const char *sp; + int rc; + bool signaled; + struct stat stat_buf; + uint32 restartLog; + uint32 restartSeg; + + /* + * When doing archive recovery, we always prefer an archived log file even + * if a file of the same name exists in XLOGDIR. The reason is that the + * file in XLOGDIR could be an old, un-filled or partly-filled version + * that was copied and restored as part of backing up $PGDATA. + * + * We could try to optimize this slightly by checking the local copy + * lastchange timestamp against the archived copy, but we have no API to + * do this, nor can we guarantee that the lastchange timestamp was + * preserved correctly when we copied to archive. Our aim is robustness, + * so we elect not to do this. + * + * If we cannot obtain the log file from the archive, however, we will try + * to use the XLOGDIR file if it exists. This is so that we can make use + * of log segments that weren't yet transferred to the archive. + * + * Notice that we don't actually overwrite any files when we copy back + * from archive because the recoveryRestoreCommand may inadvertently + * restore inappropriate xlogs, or they may be corrupt, so we may wish to + * fallback to the segments remaining in current XLOGDIR later. The + * copy-from-archive filename is always the same, ensuring that we don't + * run out of disk space on long recoveries. + */ + snprintf(xlogpath, MAXPGPATH, XLOGDIR "/%s", recovername); + + /* + * Make sure there is no existing file named recovername. + */ + if (stat(xlogpath, &stat_buf) != 0) + { + if (errno != ENOENT) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not stat file \"%s\": %m", + xlogpath))); + } + else + { + if (unlink(xlogpath) != 0) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not remove file \"%s\": %m", + xlogpath))); + } + + /* + * Calculate the archive file cutoff point for use during log shipping + * replication. All files earlier than this point can be deleted + * from the archive, though there is no requirement to do so. + * + * We initialise this with the filename of an InvalidXLogRecPtr, which + * will prevent the deletion of any WAL files from the archive + * because of the alphabetic sorting property of WAL filenames. + * + * Once we have successfully located the redo pointer of the checkpoint + * from which we start recovery we never request a file prior to the redo + * pointer of the last restartpoint. When redo begins we know that we + * have successfully located it, so there is no need for additional + * status flags to signify the point when we can begin deleting WAL files + * from the archive. + */ + if (InRedo) + { + XLByteToSeg(ControlFile->checkPointCopy.redo, + restartLog, restartSeg); + XLogFileName(lastRestartPointFname, + ControlFile->checkPointCopy.ThisTimeLineID, + restartLog, restartSeg); + /* we shouldn't need anything earlier than last restart point */ + Assert(strcmp(lastRestartPointFname, xlogfname) <= 0); + } + else + XLogFileName(lastRestartPointFname, 0, 0, 0); + + /* + * construct the command to be executed + */ + dp = xlogRestoreCmd; + endp = xlogRestoreCmd + MAXPGPATH - 1; + *endp = '\0'; + + for (sp = recoveryRestoreCommand; *sp; sp++) + { + if (*sp == '%') + { + switch (sp[1]) + { + case 'p': + /* %p: relative path of target file */ + sp++; + StrNCpy(dp, xlogpath, endp - dp); + make_native_path(dp); + dp += strlen(dp); + break; + case 'f': + /* %f: filename of desired file */ + sp++; + StrNCpy(dp, xlogfname, endp - dp); + dp += strlen(dp); + break; + case 'r': + /* %r: filename of last restartpoint */ + sp++; + StrNCpy(dp, lastRestartPointFname, endp - dp); + dp += strlen(dp); + break; + case '%': + /* convert %% to a single % */ + sp++; + if (dp < endp) + *dp++ = *sp; + break; + default: + /* otherwise treat the % as not special */ + if (dp < endp) + *dp++ = *sp; + break; + } + } + else + { + if (dp < endp) + *dp++ = *sp; + } + } + *dp = '\0'; + + ereport(DEBUG3, + (errmsg_internal("executing restore command \"%s\"", + xlogRestoreCmd))); + + /* + * Copy xlog from archival storage to XLOGDIR + */ + rc = system(xlogRestoreCmd); + if (rc == 0) + { + /* + * command apparently succeeded, but let's make sure the file is + * really there now and has the correct size. + * + * XXX I made wrong-size a fatal error to ensure the DBA would notice + * it, but is that too strong? We could try to plow ahead with a + * local copy of the file ... but the problem is that there probably + * isn't one, and we'd incorrectly conclude we've reached the end of + * WAL and we're done recovering ... + */ + if (stat(xlogpath, &stat_buf) == 0) + { + if (expectedSize > 0 && stat_buf.st_size != expectedSize) + ereport(FATAL, + (errmsg("archive file \"%s\" has wrong size: %lu instead of %lu", + xlogfname, + (unsigned long) stat_buf.st_size, + (unsigned long) expectedSize))); + else + { + ereport(LOG, + (errmsg("restored log file \"%s\" from archive", + xlogfname))); + strcpy(path, xlogpath); + return true; + } + } + else + { + /* stat failed */ + if (errno != ENOENT) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not stat file \"%s\": %m", + xlogpath))); + } + } + + /* + * Remember, we rollforward UNTIL the restore fails so failure here is + * just part of the process... that makes it difficult to determine + * whether the restore failed because there isn't an archive to restore, + * or because the administrator has specified the restore program + * incorrectly. We have to assume the former. + * + * However, if the failure was due to any sort of signal, it's best to + * punt and abort recovery. (If we "return false" here, upper levels will + * assume that recovery is complete and start up the database!) It's + * essential to abort on child SIGINT and SIGQUIT, because per spec + * system() ignores SIGINT and SIGQUIT while waiting; if we see one of + * those it's a good bet we should have gotten it too. Aborting on other + * signals such as SIGTERM seems a good idea as well. + * + * Per the Single Unix Spec, shells report exit status > 128 when a called + * command died on a signal. Also, 126 and 127 are used to report + * problems such as an unfindable command; treat those as fatal errors + * too. + */ + signaled = WIFSIGNALED(rc) || WEXITSTATUS(rc) > 125; + + ereport(signaled ? FATAL : DEBUG2, + (errmsg("could not restore file \"%s\" from archive: return code %d", + xlogfname, rc))); + + /* + * if an archived file is not available, there might still be a version of + * this file in XLOGDIR, so return that as the filename to open. + * + * In many recovery scenarios we expect this to fail also, but if so that + * just means we've reached the end of WAL. + */ + snprintf(path, MAXPGPATH, XLOGDIR "/%s", xlogfname); + return false; + } + + /* + * Preallocate log files beyond the specified log endpoint. + * + * XXX this is currently extremely conservative, since it forces only one + * future log segment to exist, and even that only if we are 75% done with + * the current one. This is only appropriate for very low-WAL-volume systems. + * High-volume systems will be OK once they've built up a sufficient set of + * recycled log segments, but the startup transient is likely to include + * a lot of segment creations by foreground processes, which is not so good. + */ + static void + PreallocXlogFiles(XLogRecPtr endptr) + { + uint32 _logId; + uint32 _logSeg; + int lf; + bool use_existent; + + XLByteToPrevSeg(endptr, _logId, _logSeg); + if ((endptr.xrecoff - 1) % XLogSegSize >= + (uint32) (0.75 * XLogSegSize)) + { + NextLogSeg(_logId, _logSeg); + use_existent = true; + lf = XLogFileInit(_logId, _logSeg, &use_existent, true); + close(lf); + if (!use_existent) + CheckpointStats.ckpt_segs_added++; + } + } + + /* + * Recycle or remove all log files older or equal to passed log/seg# + * + * endptr is current (or recent) end of xlog; this is used to determine + * whether we want to recycle rather than delete no-longer-wanted log files. + */ + static void + RemoveOldXlogFiles(uint32 log, uint32 seg, XLogRecPtr endptr) + { + uint32 endlogId; + uint32 endlogSeg; + int max_advance; + DIR *xldir; + struct dirent *xlde; + char lastoff[MAXFNAMELEN]; + char path[MAXPGPATH]; + + /* + * Initialize info about where to try to recycle to. We allow recycling + * segments up to XLOGfileslop segments beyond the current XLOG location. + */ + XLByteToPrevSeg(endptr, endlogId, endlogSeg); + max_advance = XLOGfileslop; + + xldir = AllocateDir(XLOGDIR); + if (xldir == NULL) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open transaction log directory \"%s\": %m", + XLOGDIR))); + + XLogFileName(lastoff, ThisTimeLineID, log, seg); + + while ((xlde = ReadDir(xldir, XLOGDIR)) != NULL) + { + /* + * We ignore the timeline part of the XLOG segment identifiers in + * deciding whether a segment is still needed. This ensures that we + * won't prematurely remove a segment from a parent timeline. We could + * probably be a little more proactive about removing segments of + * non-parent timelines, but that would be a whole lot more + * complicated. + * + * We use the alphanumeric sorting property of the filenames to decide + * which ones are earlier than the lastoff segment. + */ + if (strlen(xlde->d_name) == 24 && + strspn(xlde->d_name, "0123456789ABCDEF") == 24 && + strcmp(xlde->d_name + 8, lastoff + 8) <= 0) + { + if (XLogArchiveCheckDone(xlde->d_name)) + { + snprintf(path, MAXPGPATH, XLOGDIR "/%s", xlde->d_name); + + /* + * Before deleting the file, see if it can be recycled as a + * future log segment. + */ + if (InstallXLogFileSegment(&endlogId, &endlogSeg, path, + true, &max_advance, + true)) + { + ereport(DEBUG2, + (errmsg("recycled transaction log file \"%s\"", + xlde->d_name))); + CheckpointStats.ckpt_segs_recycled++; + /* Needn't recheck that slot on future iterations */ + if (max_advance > 0) + { + NextLogSeg(endlogId, endlogSeg); + max_advance--; + } + } + else + { + /* No need for any more future segments... */ + ereport(DEBUG2, + (errmsg("removing transaction log file \"%s\"", + xlde->d_name))); + unlink(path); + CheckpointStats.ckpt_segs_removed++; + } + + XLogArchiveCleanup(xlde->d_name); + } + } + } + + FreeDir(xldir); + } + + /* + * Verify whether pg_xlog and pg_xlog/archive_status exist. + * If the latter does not exist, recreate it. + * + * It is not the goal of this function to verify the contents of these + * directories, but to help in cases where someone has performed a cluster + * copy for PITR purposes but omitted pg_xlog from the copy. + * + * We could also recreate pg_xlog if it doesn't exist, but a deliberate + * policy decision was made not to. It is fairly common for pg_xlog to be + * a symlink, and if that was the DBA's intent then automatically making a + * plain directory would result in degraded performance with no notice. + */ + static void + ValidateXLOGDirectoryStructure(void) + { + char path[MAXPGPATH]; + struct stat stat_buf; + + /* Check for pg_xlog; if it doesn't exist, error out */ + if (stat(XLOGDIR, &stat_buf) != 0 || + !S_ISDIR(stat_buf.st_mode)) + ereport(FATAL, + (errmsg("required WAL directory \"%s\" does not exist", + XLOGDIR))); + + /* Check for archive_status */ + snprintf(path, MAXPGPATH, XLOGDIR "/archive_status"); + if (stat(path, &stat_buf) == 0) + { + /* Check for weird cases where it exists but isn't a directory */ + if (!S_ISDIR(stat_buf.st_mode)) + ereport(FATAL, + (errmsg("required WAL directory \"%s\" does not exist", + path))); + } + else + { + ereport(LOG, + (errmsg("creating missing WAL directory \"%s\"", path))); + if (mkdir(path, 0700) < 0) + ereport(FATAL, + (errmsg("could not create missing directory \"%s\": %m", + path))); + } + } + + /* + * Remove previous backup history files. This also retries creation of + * .ready files for any backup history files for which XLogArchiveNotify + * failed earlier. + */ + static void + CleanupBackupHistory(void) + { + DIR *xldir; + struct dirent *xlde; + char path[MAXPGPATH]; + + xldir = AllocateDir(XLOGDIR); + if (xldir == NULL) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open transaction log directory \"%s\": %m", + XLOGDIR))); + + while ((xlde = ReadDir(xldir, XLOGDIR)) != NULL) + { + if (strlen(xlde->d_name) > 24 && + strspn(xlde->d_name, "0123456789ABCDEF") == 24 && + strcmp(xlde->d_name + strlen(xlde->d_name) - strlen(".backup"), + ".backup") == 0) + { + if (XLogArchiveCheckDone(xlde->d_name)) + { + ereport(DEBUG2, + (errmsg("removing transaction log backup history file \"%s\"", + xlde->d_name))); + snprintf(path, MAXPGPATH, XLOGDIR "/%s", xlde->d_name); + unlink(path); + XLogArchiveCleanup(xlde->d_name); + } + } + } + + FreeDir(xldir); + } + + /* + * Restore the backup blocks present in an XLOG record, if any. + * + * We assume all of the record has been read into memory at *record. + * + * Note: when a backup block is available in XLOG, we restore it + * unconditionally, even if the page in the database appears newer. + * This is to protect ourselves against database pages that were partially + * or incorrectly written during a crash. We assume that the XLOG data + * must be good because it has passed a CRC check, while the database + * page might not be. This will force us to replay all subsequent + * modifications of the page that appear in XLOG, rather than possibly + * ignoring them as already applied, but that's not a huge drawback. + * + * If 'cleanup' is true, a cleanup lock is used when restoring blocks. + * Otherwise, a normal exclusive lock is used. At the moment, that's just + * pro forma, because there can't be any regular backends in the system + * during recovery. The 'cleanup' argument applies to all backup blocks + * in the WAL record, that suffices for now. + */ + void + RestoreBkpBlocks(XLogRecPtr lsn, XLogRecord *record, bool cleanup) + { + Buffer buffer; + Page page; + BkpBlock bkpb; + char *blk; + int i; + + if (!(record->xl_info & XLR_BKP_BLOCK_MASK)) + return; + + blk = (char *) XLogRecGetData(record) + record->xl_len; + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + if (!(record->xl_info & XLR_SET_BKP_BLOCK(i))) + continue; + + memcpy(&bkpb, blk, sizeof(BkpBlock)); + blk += sizeof(BkpBlock); + + buffer = XLogReadBufferExtended(bkpb.node, bkpb.fork, bkpb.block, + RBM_ZERO); + Assert(BufferIsValid(buffer)); + if (cleanup) + LockBufferForCleanup(buffer); + else + LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE); + + page = (Page) BufferGetPage(buffer); + + if (bkpb.hole_length == 0) + { + memcpy((char *) page, blk, BLCKSZ); + } + else + { + /* must zero-fill the hole */ + MemSet((char *) page, 0, BLCKSZ); + memcpy((char *) page, blk, bkpb.hole_offset); + memcpy((char *) page + (bkpb.hole_offset + bkpb.hole_length), + blk + bkpb.hole_offset, + BLCKSZ - (bkpb.hole_offset + bkpb.hole_length)); + } + + PageSetLSN(page, lsn); + PageSetTLI(page, ThisTimeLineID); + MarkBufferDirty(buffer); + UnlockReleaseBuffer(buffer); + + blk += BLCKSZ - bkpb.hole_length; + } + } + + /* + * CRC-check an XLOG record. We do not believe the contents of an XLOG + * record (other than to the minimal extent of computing the amount of + * data to read in) until we've checked the CRCs. + * + * We assume all of the record has been read into memory at *record. + */ + static bool + RecordIsValid(XLogRecord *record, XLogRecPtr recptr, int emode) + { + pg_crc32 crc; + int i; + uint32 len = record->xl_len; + BkpBlock bkpb; + char *blk; + + /* First the rmgr data */ + INIT_CRC32(crc); + COMP_CRC32(crc, XLogRecGetData(record), len); + + /* Add in the backup blocks, if any */ + blk = (char *) XLogRecGetData(record) + len; + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + uint32 blen; + + if (!(record->xl_info & XLR_SET_BKP_BLOCK(i))) + continue; + + memcpy(&bkpb, blk, sizeof(BkpBlock)); + if (bkpb.hole_offset + bkpb.hole_length > BLCKSZ) + { + ereport(emode, + (errmsg("incorrect hole size in record at %X/%X", + recptr.xlogid, recptr.xrecoff))); + return false; + } + blen = sizeof(BkpBlock) + BLCKSZ - bkpb.hole_length; + COMP_CRC32(crc, blk, blen); + blk += blen; + } + + /* Check that xl_tot_len agrees with our calculation */ + if (blk != (char *) record + record->xl_tot_len) + { + ereport(emode, + (errmsg("incorrect total length in record at %X/%X", + recptr.xlogid, recptr.xrecoff))); + return false; + } + + /* Finally include the record header */ + COMP_CRC32(crc, (char *) record + sizeof(pg_crc32), + SizeOfXLogRecord - sizeof(pg_crc32)); + FIN_CRC32(crc); + + if (!EQ_CRC32(record->xl_crc, crc)) + { + ereport(emode, + (errmsg("incorrect resource manager data checksum in record at %X/%X", + recptr.xlogid, recptr.xrecoff))); + return false; + } + + return true; + } + + /* + * Attempt to read an XLOG record. + * + * If RecPtr is not NULL, try to read a record at that position. Otherwise + * try to read a record just after the last one previously read. + * + * If no valid record is available, returns NULL, or fails if emode is PANIC. + * (emode must be either PANIC or LOG.) + * + * The record is copied into readRecordBuf, so that on successful return, + * the returned record pointer always points there. + */ + static XLogRecord * + ReadRecord(XLogRecPtr *RecPtr, int emode) + { + XLogRecord *record; + char *buffer; + XLogRecPtr tmpRecPtr = EndRecPtr; + bool randAccess = false; + uint32 len, + total_len; + uint32 targetPageOff; + uint32 targetRecOff; + uint32 pageHeaderSize; + + if (readBuf == NULL) + { + /* + * First time through, permanently allocate readBuf. We do it this + * way, rather than just making a static array, for two reasons: (1) + * no need to waste the storage in most instantiations of the backend; + * (2) a static char array isn't guaranteed to have any particular + * alignment, whereas malloc() will provide MAXALIGN'd storage. + */ + readBuf = (char *) malloc(XLOG_BLCKSZ); + Assert(readBuf != NULL); + } + + if (RecPtr == NULL) + { + RecPtr = &tmpRecPtr; + /* fast case if next record is on same page */ + if (nextRecord != NULL) + { + record = nextRecord; + goto got_record; + } + /* align old recptr to next page */ + if (tmpRecPtr.xrecoff % XLOG_BLCKSZ != 0) + tmpRecPtr.xrecoff += (XLOG_BLCKSZ - tmpRecPtr.xrecoff % XLOG_BLCKSZ); + if (tmpRecPtr.xrecoff >= XLogFileSize) + { + (tmpRecPtr.xlogid)++; + tmpRecPtr.xrecoff = 0; + } + /* We will account for page header size below */ + } + else + { + if (!XRecOffIsValid(RecPtr->xrecoff)) + ereport(PANIC, + (errmsg("invalid record offset at %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + + /* + * Since we are going to a random position in WAL, forget any prior + * state about what timeline we were in, and allow it to be any + * timeline in expectedTLIs. We also set a flag to allow curFileTLI + * to go backwards (but we can't reset that variable right here, since + * we might not change files at all). + */ + lastPageTLI = 0; /* see comment in ValidXLOGHeader */ + randAccess = true; /* allow curFileTLI to go backwards too */ + } + + if (readFile >= 0 && !XLByteInSeg(*RecPtr, readId, readSeg)) + { + close(readFile); + readFile = -1; + } + XLByteToSeg(*RecPtr, readId, readSeg); + if (readFile < 0) + { + /* Now it's okay to reset curFileTLI if random fetch */ + if (randAccess) + curFileTLI = 0; + + readFile = XLogFileRead(readId, readSeg, emode); + if (readFile < 0) + goto next_record_is_invalid; + + /* + * Whenever switching to a new WAL segment, we read the first page of + * the file and validate its header, even if that's not where the + * target record is. This is so that we can check the additional + * identification info that is present in the first page's "long" + * header. + */ + readOff = 0; + if (read(readFile, readBuf, XLOG_BLCKSZ) != XLOG_BLCKSZ) + { + ereport(emode, + (errcode_for_file_access(), + errmsg("could not read from log file %u, segment %u, offset %u: %m", + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + if (!ValidXLOGHeader((XLogPageHeader) readBuf, emode)) + goto next_record_is_invalid; + } + + targetPageOff = ((RecPtr->xrecoff % XLogSegSize) / XLOG_BLCKSZ) * XLOG_BLCKSZ; + if (readOff != targetPageOff) + { + readOff = targetPageOff; + if (lseek(readFile, (off_t) readOff, SEEK_SET) < 0) + { + ereport(emode, + (errcode_for_file_access(), + errmsg("could not seek in log file %u, segment %u to offset %u: %m", + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + if (read(readFile, readBuf, XLOG_BLCKSZ) != XLOG_BLCKSZ) + { + ereport(emode, + (errcode_for_file_access(), + errmsg("could not read from log file %u, segment %u, offset %u: %m", + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + if (!ValidXLOGHeader((XLogPageHeader) readBuf, emode)) + goto next_record_is_invalid; + } + pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) readBuf); + targetRecOff = RecPtr->xrecoff % XLOG_BLCKSZ; + if (targetRecOff == 0) + { + /* + * Can only get here in the continuing-from-prev-page case, because + * XRecOffIsValid eliminated the zero-page-offset case otherwise. Need + * to skip over the new page's header. + */ + tmpRecPtr.xrecoff += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + ereport(emode, + (errmsg("invalid record offset at %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + if ((((XLogPageHeader) readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) + { + ereport(emode, + (errmsg("contrecord is requested by %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + record = (XLogRecord *) ((char *) readBuf + RecPtr->xrecoff % XLOG_BLCKSZ); + + got_record:; + + /* + * xl_len == 0 is bad data for everything except XLOG SWITCH, where it is + * required. + */ + if (record->xl_rmid == RM_XLOG_ID && record->xl_info == XLOG_SWITCH) + { + if (record->xl_len != 0) + { + ereport(emode, + (errmsg("invalid xlog switch record at %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + } + else if (record->xl_len == 0) + { + ereport(emode, + (errmsg("record with zero length at %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + if (record->xl_tot_len < SizeOfXLogRecord + record->xl_len || + record->xl_tot_len > SizeOfXLogRecord + record->xl_len + + XLR_MAX_BKP_BLOCKS * (sizeof(BkpBlock) + BLCKSZ)) + { + ereport(emode, + (errmsg("invalid record length at %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + if (record->xl_rmid > RM_MAX_ID) + { + ereport(emode, + (errmsg("invalid resource manager ID %u at %X/%X", + record->xl_rmid, RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + if (randAccess) + { + /* + * We can't exactly verify the prev-link, but surely it should be less + * than the record's own address. + */ + if (!XLByteLT(record->xl_prev, *RecPtr)) + { + ereport(emode, + (errmsg("record with incorrect prev-link %X/%X at %X/%X", + record->xl_prev.xlogid, record->xl_prev.xrecoff, + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + } + else + { + /* + * Record's prev-link should exactly match our previous location. This + * check guards against torn WAL pages where a stale but valid-looking + * WAL record starts on a sector boundary. + */ + if (!XLByteEQ(record->xl_prev, ReadRecPtr)) + { + ereport(emode, + (errmsg("record with incorrect prev-link %X/%X at %X/%X", + record->xl_prev.xlogid, record->xl_prev.xrecoff, + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + } + + /* + * Allocate or enlarge readRecordBuf as needed. To avoid useless small + * increases, round its size to a multiple of XLOG_BLCKSZ, and make sure + * it's at least 4*Max(BLCKSZ, XLOG_BLCKSZ) to start with. (That is + * enough for all "normal" records, but very large commit or abort records + * might need more space.) + */ + total_len = record->xl_tot_len; + if (total_len > readRecordBufSize) + { + uint32 newSize = total_len; + + newSize += XLOG_BLCKSZ - (newSize % XLOG_BLCKSZ); + newSize = Max(newSize, 4 * Max(BLCKSZ, XLOG_BLCKSZ)); + if (readRecordBuf) + free(readRecordBuf); + readRecordBuf = (char *) malloc(newSize); + if (!readRecordBuf) + { + readRecordBufSize = 0; + /* We treat this as a "bogus data" condition */ + ereport(emode, + (errmsg("record length %u at %X/%X too long", + total_len, RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + readRecordBufSize = newSize; + } + + buffer = readRecordBuf; + nextRecord = NULL; + len = XLOG_BLCKSZ - RecPtr->xrecoff % XLOG_BLCKSZ; + if (total_len > len) + { + /* Need to reassemble record */ + XLogContRecord *contrecord; + uint32 gotlen = len; + + memcpy(buffer, record, len); + record = (XLogRecord *) buffer; + buffer += len; + for (;;) + { + readOff += XLOG_BLCKSZ; + if (readOff >= XLogSegSize) + { + close(readFile); + readFile = -1; + NextLogSeg(readId, readSeg); + readFile = XLogFileRead(readId, readSeg, emode); + if (readFile < 0) + goto next_record_is_invalid; + readOff = 0; + } + if (read(readFile, readBuf, XLOG_BLCKSZ) != XLOG_BLCKSZ) + { + ereport(emode, + (errcode_for_file_access(), + errmsg("could not read from log file %u, segment %u, offset %u: %m", + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + if (!ValidXLOGHeader((XLogPageHeader) readBuf, emode)) + goto next_record_is_invalid; + if (!(((XLogPageHeader) readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + ereport(emode, + (errmsg("there is no contrecord flag in log file %u, segment %u, offset %u", + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) readBuf); + contrecord = (XLogContRecord *) ((char *) readBuf + pageHeaderSize); + if (contrecord->xl_rem_len == 0 || + total_len != (contrecord->xl_rem_len + gotlen)) + { + ereport(emode, + (errmsg("invalid contrecord length %u in log file %u, segment %u, offset %u", + contrecord->xl_rem_len, + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + len = XLOG_BLCKSZ - pageHeaderSize - SizeOfXLogContRecord; + if (contrecord->xl_rem_len > len) + { + memcpy(buffer, (char *) contrecord + SizeOfXLogContRecord, len); + gotlen += len; + buffer += len; + continue; + } + memcpy(buffer, (char *) contrecord + SizeOfXLogContRecord, + contrecord->xl_rem_len); + break; + } + if (!RecordIsValid(record, *RecPtr, emode)) + goto next_record_is_invalid; + pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) readBuf); + if (XLOG_BLCKSZ - SizeOfXLogRecord >= pageHeaderSize + + MAXALIGN(SizeOfXLogContRecord + contrecord->xl_rem_len)) + { + nextRecord = (XLogRecord *) ((char *) contrecord + + MAXALIGN(SizeOfXLogContRecord + contrecord->xl_rem_len)); + } + EndRecPtr.xlogid = readId; + EndRecPtr.xrecoff = readSeg * XLogSegSize + readOff + + pageHeaderSize + + MAXALIGN(SizeOfXLogContRecord + contrecord->xl_rem_len); + ReadRecPtr = *RecPtr; + /* needn't worry about XLOG SWITCH, it can't cross page boundaries */ + return record; + } + + /* Record does not cross a page boundary */ + if (!RecordIsValid(record, *RecPtr, emode)) + goto next_record_is_invalid; + if (XLOG_BLCKSZ - SizeOfXLogRecord >= RecPtr->xrecoff % XLOG_BLCKSZ + + MAXALIGN(total_len)) + nextRecord = (XLogRecord *) ((char *) record + MAXALIGN(total_len)); + EndRecPtr.xlogid = RecPtr->xlogid; + EndRecPtr.xrecoff = RecPtr->xrecoff + MAXALIGN(total_len); + ReadRecPtr = *RecPtr; + memcpy(buffer, record, total_len); + + /* + * Special processing if it's an XLOG SWITCH record + */ + if (record->xl_rmid == RM_XLOG_ID && record->xl_info == XLOG_SWITCH) + { + /* Pretend it extends to end of segment */ + EndRecPtr.xrecoff += XLogSegSize - 1; + EndRecPtr.xrecoff -= EndRecPtr.xrecoff % XLogSegSize; + nextRecord = NULL; /* definitely not on same page */ + + /* + * Pretend that readBuf contains the last page of the segment. This is + * just to avoid Assert failure in StartupXLOG if XLOG ends with this + * segment. + */ + readOff = XLogSegSize - XLOG_BLCKSZ; + } + return (XLogRecord *) buffer; + + next_record_is_invalid:; + if (readFile >= 0) + { + close(readFile); + readFile = -1; + } + nextRecord = NULL; + return NULL; + } + + /* + * Check whether the xlog header of a page just read in looks valid. + * + * This is just a convenience subroutine to avoid duplicated code in + * ReadRecord. It's not intended for use from anywhere else. + */ + static bool + ValidXLOGHeader(XLogPageHeader hdr, int emode) + { + XLogRecPtr recaddr; + + if (hdr->xlp_magic != XLOG_PAGE_MAGIC) + { + ereport(emode, + (errmsg("invalid magic number %04X in log file %u, segment %u, offset %u", + hdr->xlp_magic, readId, readSeg, readOff))); + return false; + } + if ((hdr->xlp_info & ~XLP_ALL_FLAGS) != 0) + { + ereport(emode, + (errmsg("invalid info bits %04X in log file %u, segment %u, offset %u", + hdr->xlp_info, readId, readSeg, readOff))); + return false; + } + if (hdr->xlp_info & XLP_LONG_HEADER) + { + XLogLongPageHeader longhdr = (XLogLongPageHeader) hdr; + + if (longhdr->xlp_sysid != ControlFile->system_identifier) + { + char fhdrident_str[32]; + char sysident_str[32]; + + /* + * Format sysids separately to keep platform-dependent format code + * out of the translatable message string. + */ + snprintf(fhdrident_str, sizeof(fhdrident_str), UINT64_FORMAT, + longhdr->xlp_sysid); + snprintf(sysident_str, sizeof(sysident_str), UINT64_FORMAT, + ControlFile->system_identifier); + ereport(emode, + (errmsg("WAL file is from different system"), + errdetail("WAL file SYSID is %s, pg_control SYSID is %s", + fhdrident_str, sysident_str))); + return false; + } + if (longhdr->xlp_seg_size != XLogSegSize) + { + ereport(emode, + (errmsg("WAL file is from different system"), + errdetail("Incorrect XLOG_SEG_SIZE in page header."))); + return false; + } + if (longhdr->xlp_xlog_blcksz != XLOG_BLCKSZ) + { + ereport(emode, + (errmsg("WAL file is from different system"), + errdetail("Incorrect XLOG_BLCKSZ in page header."))); + return false; + } + } + else if (readOff == 0) + { + /* hmm, first page of file doesn't have a long header? */ + ereport(emode, + (errmsg("invalid info bits %04X in log file %u, segment %u, offset %u", + hdr->xlp_info, readId, readSeg, readOff))); + return false; + } + + recaddr.xlogid = readId; + recaddr.xrecoff = readSeg * XLogSegSize + readOff; + if (!XLByteEQ(hdr->xlp_pageaddr, recaddr)) + { + ereport(emode, + (errmsg("unexpected pageaddr %X/%X in log file %u, segment %u, offset %u", + hdr->xlp_pageaddr.xlogid, hdr->xlp_pageaddr.xrecoff, + readId, readSeg, readOff))); + return false; + } + + /* + * Check page TLI is one of the expected values. + */ + if (!list_member_int(expectedTLIs, (int) hdr->xlp_tli)) + { + ereport(emode, + (errmsg("unexpected timeline ID %u in log file %u, segment %u, offset %u", + hdr->xlp_tli, + readId, readSeg, readOff))); + return false; + } + + /* + * Since child timelines are always assigned a TLI greater than their + * immediate parent's TLI, we should never see TLI go backwards across + * successive pages of a consistent WAL sequence. + * + * Of course this check should only be applied when advancing sequentially + * across pages; therefore ReadRecord resets lastPageTLI to zero when + * going to a random page. + */ + if (hdr->xlp_tli < lastPageTLI) + { + ereport(emode, + (errmsg("out-of-sequence timeline ID %u (after %u) in log file %u, segment %u, offset %u", + hdr->xlp_tli, lastPageTLI, + readId, readSeg, readOff))); + return false; + } + lastPageTLI = hdr->xlp_tli; + return true; + } + + /* + * Try to read a timeline's history file. + * + * If successful, return the list of component TLIs (the given TLI followed by + * its ancestor TLIs). If we can't find the history file, assume that the + * timeline has no parents, and return a list of just the specified timeline + * ID. + */ + static List * + readTimeLineHistory(TimeLineID targetTLI) + { + List *result; + char path[MAXPGPATH]; + char histfname[MAXFNAMELEN]; + char fline[MAXPGPATH]; + FILE *fd; + + if (InArchiveRecovery) + { + TLHistoryFileName(histfname, targetTLI); + RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0); + } + else + TLHistoryFilePath(path, targetTLI); + + fd = AllocateFile(path, "r"); + if (fd == NULL) + { + if (errno != ENOENT) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not open file \"%s\": %m", path))); + /* Not there, so assume no parents */ + return list_make1_int((int) targetTLI); + } + + result = NIL; + + /* + * Parse the file... + */ + while (fgets(fline, sizeof(fline), fd) != NULL) + { + /* skip leading whitespace and check for # comment */ + char *ptr; + char *endptr; + TimeLineID tli; + + for (ptr = fline; *ptr; ptr++) + { + if (!isspace((unsigned char) *ptr)) + break; + } + if (*ptr == '\0' || *ptr == '#') + continue; + + /* expect a numeric timeline ID as first field of line */ + tli = (TimeLineID) strtoul(ptr, &endptr, 0); + if (endptr == ptr) + ereport(FATAL, + (errmsg("syntax error in history file: %s", fline), + errhint("Expected a numeric timeline ID."))); + + if (result && + tli <= (TimeLineID) linitial_int(result)) + ereport(FATAL, + (errmsg("invalid data in history file: %s", fline), + errhint("Timeline IDs must be in increasing sequence."))); + + /* Build list with newest item first */ + result = lcons_int((int) tli, result); + + /* we ignore the remainder of each line */ + } + + FreeFile(fd); + + if (result && + targetTLI <= (TimeLineID) linitial_int(result)) + ereport(FATAL, + (errmsg("invalid data in history file \"%s\"", path), + errhint("Timeline IDs must be less than child timeline's ID."))); + + result = lcons_int((int) targetTLI, result); + + ereport(DEBUG3, + (errmsg_internal("history of timeline %u is %s", + targetTLI, nodeToString(result)))); + + return result; + } + + /* + * Probe whether a timeline history file exists for the given timeline ID + */ + static bool + existsTimeLineHistory(TimeLineID probeTLI) + { + char path[MAXPGPATH]; + char histfname[MAXFNAMELEN]; + FILE *fd; + + if (InArchiveRecovery) + { + TLHistoryFileName(histfname, probeTLI); + RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0); + } + else + TLHistoryFilePath(path, probeTLI); + + fd = AllocateFile(path, "r"); + if (fd != NULL) + { + FreeFile(fd); + return true; + } + else + { + if (errno != ENOENT) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not open file \"%s\": %m", path))); + return false; + } + } + + /* + * Find the newest existing timeline, assuming that startTLI exists. + * + * Note: while this is somewhat heuristic, it does positively guarantee + * that (result + 1) is not a known timeline, and therefore it should + * be safe to assign that ID to a new timeline. + */ + static TimeLineID + findNewestTimeLine(TimeLineID startTLI) + { + TimeLineID newestTLI; + TimeLineID probeTLI; + + /* + * The algorithm is just to probe for the existence of timeline history + * files. XXX is it useful to allow gaps in the sequence? + */ + newestTLI = startTLI; + + for (probeTLI = startTLI + 1;; probeTLI++) + { + if (existsTimeLineHistory(probeTLI)) + { + newestTLI = probeTLI; /* probeTLI exists */ + } + else + { + /* doesn't exist, assume we're done */ + break; + } + } + + return newestTLI; + } + + /* + * Create a new timeline history file. + * + * newTLI: ID of the new timeline + * parentTLI: ID of its immediate parent + * endTLI et al: ID of the last used WAL file, for annotation purposes + * + * Currently this is only used during recovery, and so there are no locking + * considerations. But we should be just as tense as XLogFileInit to avoid + * emplacing a bogus file. + */ + static void + writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI, + TimeLineID endTLI, uint32 endLogId, uint32 endLogSeg) + { + char path[MAXPGPATH]; + char tmppath[MAXPGPATH]; + char histfname[MAXFNAMELEN]; + char xlogfname[MAXFNAMELEN]; + char buffer[BLCKSZ]; + int srcfd; + int fd; + int nbytes; + + Assert(newTLI > parentTLI); /* else bad selection of newTLI */ + + /* + * Write into a temp file name. + */ + snprintf(tmppath, MAXPGPATH, XLOGDIR "/xlogtemp.%d", (int) getpid()); + + unlink(tmppath); + + /* do not use get_sync_bit() here --- want to fsync only at end of fill */ + fd = BasicOpenFile(tmppath, O_RDWR | O_CREAT | O_EXCL, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not create file \"%s\": %m", tmppath))); + + /* + * If a history file exists for the parent, copy it verbatim + */ + if (InArchiveRecovery) + { + TLHistoryFileName(histfname, parentTLI); + RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0); + } + else + TLHistoryFilePath(path, parentTLI); + + srcfd = BasicOpenFile(path, O_RDONLY, 0); + if (srcfd < 0) + { + if (errno != ENOENT) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open file \"%s\": %m", path))); + /* Not there, so assume parent has no parents */ + } + else + { + for (;;) + { + errno = 0; + nbytes = (int) read(srcfd, buffer, sizeof(buffer)); + if (nbytes < 0 || errno != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", path))); + if (nbytes == 0) + break; + errno = 0; + if ((int) write(fd, buffer, nbytes) != nbytes) + { + int save_errno = errno; + + /* + * If we fail to make the file, delete it to release disk + * space + */ + unlink(tmppath); + + /* + * if write didn't set errno, assume problem is no disk space + */ + errno = save_errno ? save_errno : ENOSPC; + + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write to file \"%s\": %m", tmppath))); + } + } + close(srcfd); + } + + /* + * Append one line with the details of this timeline split. + * + * If we did have a parent file, insert an extra newline just in case the + * parent file failed to end with one. + */ + XLogFileName(xlogfname, endTLI, endLogId, endLogSeg); + + snprintf(buffer, sizeof(buffer), + "%s%u\t%s\t%s transaction %u at %s\n", + (srcfd < 0) ? "" : "\n", + parentTLI, + xlogfname, + recoveryStopAfter ? "after" : "before", + recoveryStopXid, + timestamptz_to_str(recoveryStopTime)); + + nbytes = strlen(buffer); + errno = 0; + if ((int) write(fd, buffer, nbytes) != nbytes) + { + int save_errno = errno; + + /* + * If we fail to make the file, delete it to release disk space + */ + unlink(tmppath); + /* if write didn't set errno, assume problem is no disk space */ + errno = save_errno ? save_errno : ENOSPC; + + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write to file \"%s\": %m", tmppath))); + } + + if (pg_fsync(fd) != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not fsync file \"%s\": %m", tmppath))); + + if (close(fd)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not close file \"%s\": %m", tmppath))); + + + /* + * Now move the completed history file into place with its final name. + */ + TLHistoryFilePath(path, newTLI); + + /* + * Prefer link() to rename() here just to be really sure that we don't + * overwrite an existing logfile. However, there shouldn't be one, so + * rename() is an acceptable substitute except for the truly paranoid. + */ + #if HAVE_WORKING_LINK + if (link(tmppath, path) < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not link file \"%s\" to \"%s\": %m", + tmppath, path))); + unlink(tmppath); + #else + if (rename(tmppath, path) < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\": %m", + tmppath, path))); + #endif + + /* The history file can be archived immediately. */ + TLHistoryFileName(histfname, newTLI); + XLogArchiveNotify(histfname); + } + + /* + * I/O routines for pg_control + * + * *ControlFile is a buffer in shared memory that holds an image of the + * contents of pg_control. WriteControlFile() initializes pg_control + * given a preloaded buffer, ReadControlFile() loads the buffer from + * the pg_control file (during postmaster or standalone-backend startup), + * and UpdateControlFile() rewrites pg_control after we modify xlog state. + * + * For simplicity, WriteControlFile() initializes the fields of pg_control + * that are related to checking backend/database compatibility, and + * ReadControlFile() verifies they are correct. We could split out the + * I/O and compatibility-check functions, but there seems no need currently. + */ + static void + WriteControlFile(void) + { + int fd; + char buffer[PG_CONTROL_SIZE]; /* need not be aligned */ + + /* + * Initialize version and compatibility-check fields + */ + ControlFile->pg_control_version = PG_CONTROL_VERSION; + ControlFile->catalog_version_no = CATALOG_VERSION_NO; + + ControlFile->maxAlign = MAXIMUM_ALIGNOF; + ControlFile->floatFormat = FLOATFORMAT_VALUE; + + ControlFile->blcksz = BLCKSZ; + ControlFile->relseg_size = RELSEG_SIZE; + ControlFile->xlog_blcksz = XLOG_BLCKSZ; + ControlFile->xlog_seg_size = XLOG_SEG_SIZE; + + ControlFile->nameDataLen = NAMEDATALEN; + ControlFile->indexMaxKeys = INDEX_MAX_KEYS; + + ControlFile->toast_max_chunk_size = TOAST_MAX_CHUNK_SIZE; + + #ifdef HAVE_INT64_TIMESTAMP + ControlFile->enableIntTimes = true; + #else + ControlFile->enableIntTimes = false; + #endif + ControlFile->float4ByVal = FLOAT4PASSBYVAL; + ControlFile->float8ByVal = FLOAT8PASSBYVAL; + + /* Contents are protected with a CRC */ + INIT_CRC32(ControlFile->crc); + COMP_CRC32(ControlFile->crc, + (char *) ControlFile, + offsetof(ControlFileData, crc)); + FIN_CRC32(ControlFile->crc); + + /* + * We write out PG_CONTROL_SIZE bytes into pg_control, zero-padding the + * excess over sizeof(ControlFileData). This reduces the odds of + * premature-EOF errors when reading pg_control. We'll still fail when we + * check the contents of the file, but hopefully with a more specific + * error than "couldn't read pg_control". + */ + if (sizeof(ControlFileData) > PG_CONTROL_SIZE) + elog(PANIC, "sizeof(ControlFileData) is larger than PG_CONTROL_SIZE; fix either one"); + + memset(buffer, 0, PG_CONTROL_SIZE); + memcpy(buffer, ControlFile, sizeof(ControlFileData)); + + fd = BasicOpenFile(XLOG_CONTROL_FILE, + O_RDWR | O_CREAT | O_EXCL | PG_BINARY, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not create control file \"%s\": %m", + XLOG_CONTROL_FILE))); + + errno = 0; + if (write(fd, buffer, PG_CONTROL_SIZE) != PG_CONTROL_SIZE) + { + /* if write didn't set errno, assume problem is no disk space */ + if (errno == 0) + errno = ENOSPC; + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not write to control file: %m"))); + } + + if (pg_fsync(fd) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync control file: %m"))); + + if (close(fd)) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not close control file: %m"))); + } + + static void + ReadControlFile(void) + { + pg_crc32 crc; + int fd; + + /* + * Read data... + */ + fd = BasicOpenFile(XLOG_CONTROL_FILE, + O_RDWR | PG_BINARY, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not open control file \"%s\": %m", + XLOG_CONTROL_FILE))); + + if (read(fd, ControlFile, sizeof(ControlFileData)) != sizeof(ControlFileData)) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not read from control file: %m"))); + + close(fd); + + /* + * Check for expected pg_control format version. If this is wrong, the + * CRC check will likely fail because we'll be checking the wrong number + * of bytes. Complaining about wrong version will probably be more + * enlightening than complaining about wrong CRC. + */ + + if (ControlFile->pg_control_version != PG_CONTROL_VERSION && ControlFile->pg_control_version % 65536 == 0 && ControlFile->pg_control_version / 65536 != 0) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with PG_CONTROL_VERSION %d (0x%08x)," + " but the server was compiled with PG_CONTROL_VERSION %d (0x%08x).", + ControlFile->pg_control_version, ControlFile->pg_control_version, + PG_CONTROL_VERSION, PG_CONTROL_VERSION), + errhint("This could be a problem of mismatched byte ordering. It looks like you need to initdb."))); + + if (ControlFile->pg_control_version != PG_CONTROL_VERSION) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with PG_CONTROL_VERSION %d," + " but the server was compiled with PG_CONTROL_VERSION %d.", + ControlFile->pg_control_version, PG_CONTROL_VERSION), + errhint("It looks like you need to initdb."))); + + /* Now check the CRC. */ + INIT_CRC32(crc); + COMP_CRC32(crc, + (char *) ControlFile, + offsetof(ControlFileData, crc)); + FIN_CRC32(crc); + + if (!EQ_CRC32(crc, ControlFile->crc)) + ereport(FATAL, + (errmsg("incorrect checksum in control file"))); + + /* + * Do compatibility checking immediately. We do this here for 2 reasons: + * + * (1) if the database isn't compatible with the backend executable, we + * want to abort before we can possibly do any damage; + * + * (2) this code is executed in the postmaster, so the setlocale() will + * propagate to forked backends, which aren't going to read this file for + * themselves. (These locale settings are considered critical + * compatibility items because they can affect sort order of indexes.) + */ + if (ControlFile->catalog_version_no != CATALOG_VERSION_NO) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with CATALOG_VERSION_NO %d," + " but the server was compiled with CATALOG_VERSION_NO %d.", + ControlFile->catalog_version_no, CATALOG_VERSION_NO), + errhint("It looks like you need to initdb."))); + if (ControlFile->maxAlign != MAXIMUM_ALIGNOF) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with MAXALIGN %d," + " but the server was compiled with MAXALIGN %d.", + ControlFile->maxAlign, MAXIMUM_ALIGNOF), + errhint("It looks like you need to initdb."))); + if (ControlFile->floatFormat != FLOATFORMAT_VALUE) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster appears to use a different floating-point number format than the server executable."), + errhint("It looks like you need to initdb."))); + if (ControlFile->blcksz != BLCKSZ) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with BLCKSZ %d," + " but the server was compiled with BLCKSZ %d.", + ControlFile->blcksz, BLCKSZ), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->relseg_size != RELSEG_SIZE) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with RELSEG_SIZE %d," + " but the server was compiled with RELSEG_SIZE %d.", + ControlFile->relseg_size, RELSEG_SIZE), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->xlog_blcksz != XLOG_BLCKSZ) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with XLOG_BLCKSZ %d," + " but the server was compiled with XLOG_BLCKSZ %d.", + ControlFile->xlog_blcksz, XLOG_BLCKSZ), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->xlog_seg_size != XLOG_SEG_SIZE) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with XLOG_SEG_SIZE %d," + " but the server was compiled with XLOG_SEG_SIZE %d.", + ControlFile->xlog_seg_size, XLOG_SEG_SIZE), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->nameDataLen != NAMEDATALEN) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with NAMEDATALEN %d," + " but the server was compiled with NAMEDATALEN %d.", + ControlFile->nameDataLen, NAMEDATALEN), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->indexMaxKeys != INDEX_MAX_KEYS) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with INDEX_MAX_KEYS %d," + " but the server was compiled with INDEX_MAX_KEYS %d.", + ControlFile->indexMaxKeys, INDEX_MAX_KEYS), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->toast_max_chunk_size != TOAST_MAX_CHUNK_SIZE) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with TOAST_MAX_CHUNK_SIZE %d," + " but the server was compiled with TOAST_MAX_CHUNK_SIZE %d.", + ControlFile->toast_max_chunk_size, (int) TOAST_MAX_CHUNK_SIZE), + errhint("It looks like you need to recompile or initdb."))); + + #ifdef HAVE_INT64_TIMESTAMP + if (ControlFile->enableIntTimes != true) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized without HAVE_INT64_TIMESTAMP" + " but the server was compiled with HAVE_INT64_TIMESTAMP."), + errhint("It looks like you need to recompile or initdb."))); + #else + if (ControlFile->enableIntTimes != false) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with HAVE_INT64_TIMESTAMP" + " but the server was compiled without HAVE_INT64_TIMESTAMP."), + errhint("It looks like you need to recompile or initdb."))); + #endif + + #ifdef USE_FLOAT4_BYVAL + if (ControlFile->float4ByVal != true) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized without USE_FLOAT4_BYVAL" + " but the server was compiled with USE_FLOAT4_BYVAL."), + errhint("It looks like you need to recompile or initdb."))); + #else + if (ControlFile->float4ByVal != false) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with USE_FLOAT4_BYVAL" + " but the server was compiled without USE_FLOAT4_BYVAL."), + errhint("It looks like you need to recompile or initdb."))); + #endif + + #ifdef USE_FLOAT8_BYVAL + if (ControlFile->float8ByVal != true) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized without USE_FLOAT8_BYVAL" + " but the server was compiled with USE_FLOAT8_BYVAL."), + errhint("It looks like you need to recompile or initdb."))); + #else + if (ControlFile->float8ByVal != false) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with USE_FLOAT8_BYVAL" + " but the server was compiled without USE_FLOAT8_BYVAL."), + errhint("It looks like you need to recompile or initdb."))); + #endif + } + + void + UpdateControlFile(void) + { + int fd; + + INIT_CRC32(ControlFile->crc); + COMP_CRC32(ControlFile->crc, + (char *) ControlFile, + offsetof(ControlFileData, crc)); + FIN_CRC32(ControlFile->crc); + + fd = BasicOpenFile(XLOG_CONTROL_FILE, + O_RDWR | PG_BINARY, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not open control file \"%s\": %m", + XLOG_CONTROL_FILE))); + + errno = 0; + if (write(fd, ControlFile, sizeof(ControlFileData)) != sizeof(ControlFileData)) + { + /* if write didn't set errno, assume problem is no disk space */ + if (errno == 0) + errno = ENOSPC; + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not write to control file: %m"))); + } + + if (pg_fsync(fd) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync control file: %m"))); + + if (close(fd)) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not close control file: %m"))); + } + + /* + * Initialization of shared memory for XLOG + */ + Size + XLOGShmemSize(void) + { + Size size; + + /* XLogCtl */ + size = sizeof(XLogCtlData); + /* xlblocks array */ + size = add_size(size, mul_size(sizeof(XLogRecPtr), XLOGbuffers)); + /* extra alignment padding for XLOG I/O buffers */ + size = add_size(size, ALIGNOF_XLOG_BUFFER); + /* and the buffers themselves */ + size = add_size(size, mul_size(XLOG_BLCKSZ, XLOGbuffers)); + + /* + * Note: we don't count ControlFileData, it comes out of the "slop factor" + * added by CreateSharedMemoryAndSemaphores. This lets us use this + * routine again below to compute the actual allocation size. + */ + + return size; + } + + void + XLOGShmemInit(void) + { + bool foundCFile, + foundXLog; + char *allocptr; + + ControlFile = (ControlFileData *) + ShmemInitStruct("Control File", sizeof(ControlFileData), &foundCFile); + XLogCtl = (XLogCtlData *) + ShmemInitStruct("XLOG Ctl", XLOGShmemSize(), &foundXLog); + + if (foundCFile || foundXLog) + { + /* both should be present or neither */ + Assert(foundCFile && foundXLog); + return; + } + + memset(XLogCtl, 0, sizeof(XLogCtlData)); + + /* + * Since XLogCtlData contains XLogRecPtr fields, its sizeof should be a + * multiple of the alignment for same, so no extra alignment padding is + * needed here. + */ + allocptr = ((char *) XLogCtl) + sizeof(XLogCtlData); + XLogCtl->xlblocks = (XLogRecPtr *) allocptr; + memset(XLogCtl->xlblocks, 0, sizeof(XLogRecPtr) * XLOGbuffers); + allocptr += sizeof(XLogRecPtr) * XLOGbuffers; + + /* + * Align the start of the page buffers to an ALIGNOF_XLOG_BUFFER boundary. + */ + allocptr = (char *) TYPEALIGN(ALIGNOF_XLOG_BUFFER, allocptr); + XLogCtl->pages = allocptr; + memset(XLogCtl->pages, 0, (Size) XLOG_BLCKSZ * XLOGbuffers); + + /* + * Do basic initialization of XLogCtl shared data. (StartupXLOG will fill + * in additional info.) + */ + XLogCtl->XLogCacheBlck = XLOGbuffers - 1; + XLogCtl->Insert.currpage = (XLogPageHeader) (XLogCtl->pages); + SpinLockInit(&XLogCtl->info_lck); + + /* + * If we are not in bootstrap mode, pg_control should already exist. Read + * and validate it immediately (see comments in ReadControlFile() for the + * reasons why). + */ + if (!IsBootstrapProcessingMode()) + ReadControlFile(); + } + + /* + * This func must be called ONCE on system install. It creates pg_control + * and the initial XLOG segment. + */ + void + BootStrapXLOG(void) + { + CheckPoint checkPoint; + char *buffer; + XLogPageHeader page; + XLogLongPageHeader longpage; + XLogRecord *record; + bool use_existent; + uint64 sysidentifier; + struct timeval tv; + pg_crc32 crc; + + /* + * Select a hopefully-unique system identifier code for this installation. + * We use the result of gettimeofday(), including the fractional seconds + * field, as being about as unique as we can easily get. (Think not to + * use random(), since it hasn't been seeded and there's no portable way + * to seed it other than the system clock value...) The upper half of the + * uint64 value is just the tv_sec part, while the lower half is the XOR + * of tv_sec and tv_usec. This is to ensure that we don't lose uniqueness + * unnecessarily if "uint64" is really only 32 bits wide. A person + * knowing this encoding can determine the initialization time of the + * installation, which could perhaps be useful sometimes. + */ + gettimeofday(&tv, NULL); + sysidentifier = ((uint64) tv.tv_sec) << 32; + sysidentifier |= (uint32) (tv.tv_sec | tv.tv_usec); + + /* First timeline ID is always 1 */ + ThisTimeLineID = 1; + + /* page buffer must be aligned suitably for O_DIRECT */ + buffer = (char *) palloc(XLOG_BLCKSZ + ALIGNOF_XLOG_BUFFER); + page = (XLogPageHeader) TYPEALIGN(ALIGNOF_XLOG_BUFFER, buffer); + memset(page, 0, XLOG_BLCKSZ); + + /* Set up information for the initial checkpoint record */ + checkPoint.redo.xlogid = 0; + checkPoint.redo.xrecoff = SizeOfXLogLongPHD; + checkPoint.ThisTimeLineID = ThisTimeLineID; + checkPoint.nextXidEpoch = 0; + checkPoint.nextXid = FirstNormalTransactionId; + checkPoint.nextOid = FirstBootstrapObjectId; + checkPoint.nextMulti = FirstMultiXactId; + checkPoint.nextMultiOffset = 0; + checkPoint.time = (pg_time_t) time(NULL); + + ShmemVariableCache->nextXid = checkPoint.nextXid; + ShmemVariableCache->nextOid = checkPoint.nextOid; + ShmemVariableCache->oidCount = 0; + MultiXactSetNextMXact(checkPoint.nextMulti, checkPoint.nextMultiOffset); + + /* Set up the XLOG page header */ + page->xlp_magic = XLOG_PAGE_MAGIC; + page->xlp_info = XLP_LONG_HEADER; + page->xlp_tli = ThisTimeLineID; + page->xlp_pageaddr.xlogid = 0; + page->xlp_pageaddr.xrecoff = 0; + longpage = (XLogLongPageHeader) page; + longpage->xlp_sysid = sysidentifier; + longpage->xlp_seg_size = XLogSegSize; + longpage->xlp_xlog_blcksz = XLOG_BLCKSZ; + + /* Insert the initial checkpoint record */ + record = (XLogRecord *) ((char *) page + SizeOfXLogLongPHD); + record->xl_prev.xlogid = 0; + record->xl_prev.xrecoff = 0; + record->xl_xid = InvalidTransactionId; + record->xl_tot_len = SizeOfXLogRecord + sizeof(checkPoint); + record->xl_len = sizeof(checkPoint); + record->xl_info = XLOG_CHECKPOINT_SHUTDOWN; + record->xl_rmid = RM_XLOG_ID; + memcpy(XLogRecGetData(record), &checkPoint, sizeof(checkPoint)); + + INIT_CRC32(crc); + COMP_CRC32(crc, &checkPoint, sizeof(checkPoint)); + COMP_CRC32(crc, (char *) record + sizeof(pg_crc32), + SizeOfXLogRecord - sizeof(pg_crc32)); + FIN_CRC32(crc); + record->xl_crc = crc; + + /* Create first XLOG segment file */ + use_existent = false; + openLogFile = XLogFileInit(0, 0, &use_existent, false); + + /* Write the first page with the initial record */ + errno = 0; + if (write(openLogFile, page, XLOG_BLCKSZ) != XLOG_BLCKSZ) + { + /* if write didn't set errno, assume problem is no disk space */ + if (errno == 0) + errno = ENOSPC; + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not write bootstrap transaction log file: %m"))); + } + + if (pg_fsync(openLogFile) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync bootstrap transaction log file: %m"))); + + if (close(openLogFile)) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not close bootstrap transaction log file: %m"))); + + openLogFile = -1; + + /* Now create pg_control */ + + memset(ControlFile, 0, sizeof(ControlFileData)); + /* Initialize pg_control status fields */ + ControlFile->system_identifier = sysidentifier; + ControlFile->state = DB_SHUTDOWNED; + ControlFile->time = checkPoint.time; + ControlFile->checkPoint = checkPoint.redo; + ControlFile->checkPointCopy = checkPoint; + /* some additional ControlFile fields are set in WriteControlFile() */ + + WriteControlFile(); + + /* Bootstrap the commit log, too */ + BootStrapCLOG(); + BootStrapSUBTRANS(); + BootStrapMultiXact(); + + pfree(buffer); + } + + static char * + str_time(pg_time_t tnow) + { + static char buf[128]; + + pg_strftime(buf, sizeof(buf), + "%Y-%m-%d %H:%M:%S %Z", + pg_localtime(&tnow, log_timezone)); + + return buf; + } + + /* + * See if there is a recovery command file (recovery.conf), and if so + * read in parameters for archive recovery. + * + * XXX longer term intention is to expand this to + * cater for additional parameters and controls + * possibly use a flex lexer similar to the GUC one + */ + static void + readRecoveryCommandFile(void) + { + FILE *fd; + char cmdline[MAXPGPATH]; + TimeLineID rtli = 0; + bool rtliGiven = false; + bool syntaxError = false; + + fd = AllocateFile(RECOVERY_COMMAND_FILE, "r"); + if (fd == NULL) + { + if (errno == ENOENT) + return; /* not there, so no archive recovery */ + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not open recovery command file \"%s\": %m", + RECOVERY_COMMAND_FILE))); + } + + ereport(LOG, + (errmsg("starting archive recovery"))); + + /* + * Parse the file... + */ + while (fgets(cmdline, sizeof(cmdline), fd) != NULL) + { + /* skip leading whitespace and check for # comment */ + char *ptr; + char *tok1; + char *tok2; + + for (ptr = cmdline; *ptr; ptr++) + { + if (!isspace((unsigned char) *ptr)) + break; + } + if (*ptr == '\0' || *ptr == '#') + continue; + + /* identify the quoted parameter value */ + tok1 = strtok(ptr, "'"); + if (!tok1) + { + syntaxError = true; + break; + } + tok2 = strtok(NULL, "'"); + if (!tok2) + { + syntaxError = true; + break; + } + /* reparse to get just the parameter name */ + tok1 = strtok(ptr, " \t="); + if (!tok1) + { + syntaxError = true; + break; + } + + if (strcmp(tok1, "restore_command") == 0) + { + recoveryRestoreCommand = pstrdup(tok2); + ereport(LOG, + (errmsg("restore_command = '%s'", + recoveryRestoreCommand))); + } + else if (strcmp(tok1, "recovery_target_timeline") == 0) + { + rtliGiven = true; + if (strcmp(tok2, "latest") == 0) + rtli = 0; + else + { + errno = 0; + rtli = (TimeLineID) strtoul(tok2, NULL, 0); + if (errno == EINVAL || errno == ERANGE) + ereport(FATAL, + (errmsg("recovery_target_timeline is not a valid number: \"%s\"", + tok2))); + } + if (rtli) + ereport(LOG, + (errmsg("recovery_target_timeline = %u", rtli))); + else + ereport(LOG, + (errmsg("recovery_target_timeline = latest"))); + } + else if (strcmp(tok1, "recovery_target_xid") == 0) + { + errno = 0; + recoveryTargetXid = (TransactionId) strtoul(tok2, NULL, 0); + if (errno == EINVAL || errno == ERANGE) + ereport(FATAL, + (errmsg("recovery_target_xid is not a valid number: \"%s\"", + tok2))); + ereport(LOG, + (errmsg("recovery_target_xid = %u", + recoveryTargetXid))); + recoveryTarget = true; + recoveryTargetExact = true; + } + else if (strcmp(tok1, "recovery_target_time") == 0) + { + /* + * if recovery_target_xid specified, then this overrides + * recovery_target_time + */ + if (recoveryTargetExact) + continue; + recoveryTarget = true; + recoveryTargetExact = false; + + /* + * Convert the time string given by the user to TimestampTz form. + */ + recoveryTargetTime = + DatumGetTimestampTz(DirectFunctionCall3(timestamptz_in, + CStringGetDatum(tok2), + ObjectIdGetDatum(InvalidOid), + Int32GetDatum(-1))); + ereport(LOG, + (errmsg("recovery_target_time = '%s'", + timestamptz_to_str(recoveryTargetTime)))); + } + else if (strcmp(tok1, "recovery_target_inclusive") == 0) + { + /* + * does nothing if a recovery_target is not also set + */ + if (!parse_bool(tok2, &recoveryTargetInclusive)) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("parameter \"recovery_target_inclusive\" requires a Boolean value"))); + ereport(LOG, + (errmsg("recovery_target_inclusive = %s", tok2))); + } + else if (strcmp(tok1, "log_restartpoints") == 0) + { + /* + * does nothing if a recovery_target is not also set + */ + if (!parse_bool(tok2, &recoveryLogRestartpoints)) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("parameter \"log_restartpoints\" requires a Boolean value"))); + ereport(LOG, + (errmsg("log_restartpoints = %s", tok2))); + } + else + ereport(FATAL, + (errmsg("unrecognized recovery parameter \"%s\"", + tok1))); + } + + FreeFile(fd); + + if (syntaxError) + ereport(FATAL, + (errmsg("syntax error in recovery command file: %s", + cmdline), + errhint("Lines should have the format parameter = 'value'."))); + + /* Check that required parameters were supplied */ + if (recoveryRestoreCommand == NULL) + ereport(FATAL, + (errmsg("recovery command file \"%s\" did not specify restore_command", + RECOVERY_COMMAND_FILE))); + + /* Enable fetching from archive recovery area */ + InArchiveRecovery = true; + + /* + * If user specified recovery_target_timeline, validate it or compute the + * "latest" value. We can't do this until after we've gotten the restore + * command and set InArchiveRecovery, because we need to fetch timeline + * history files from the archive. + */ + if (rtliGiven) + { + if (rtli) + { + /* Timeline 1 does not have a history file, all else should */ + if (rtli != 1 && !existsTimeLineHistory(rtli)) + ereport(FATAL, + (errmsg("recovery target timeline %u does not exist", + rtli))); + recoveryTargetTLI = rtli; + } + else + { + /* We start the "latest" search from pg_control's timeline */ + recoveryTargetTLI = findNewestTimeLine(recoveryTargetTLI); + } + } + } + + /* + * Exit archive-recovery state + */ + static void + exitArchiveRecovery(TimeLineID endTLI, uint32 endLogId, uint32 endLogSeg) + { + char recoveryPath[MAXPGPATH]; + char xlogpath[MAXPGPATH]; + + /* + * We are no longer in archive recovery state. + */ + InArchiveRecovery = false; + + /* + * We should have the ending log segment currently open. Verify, and then + * close it (to avoid problems on Windows with trying to rename or delete + * an open file). + */ + Assert(readFile >= 0); + Assert(readId == endLogId); + Assert(readSeg == endLogSeg); + + close(readFile); + readFile = -1; + + /* + * If the segment was fetched from archival storage, we want to replace + * the existing xlog segment (if any) with the archival version. This is + * because whatever is in XLOGDIR is very possibly older than what we have + * from the archives, since it could have come from restoring a PGDATA + * backup. In any case, the archival version certainly is more + * descriptive of what our current database state is, because that is what + * we replayed from. + * + * Note that if we are establishing a new timeline, ThisTimeLineID is + * already set to the new value, and so we will create a new file instead + * of overwriting any existing file. (This is, in fact, always the case + * at present.) + */ + snprintf(recoveryPath, MAXPGPATH, XLOGDIR "/RECOVERYXLOG"); + XLogFilePath(xlogpath, ThisTimeLineID, endLogId, endLogSeg); + + if (restoredFromArchive) + { + ereport(DEBUG3, + (errmsg_internal("moving last restored xlog to \"%s\"", + xlogpath))); + unlink(xlogpath); /* might or might not exist */ + if (rename(recoveryPath, xlogpath) != 0) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\": %m", + recoveryPath, xlogpath))); + /* XXX might we need to fix permissions on the file? */ + } + else + { + /* + * If the latest segment is not archival, but there's still a + * RECOVERYXLOG laying about, get rid of it. + */ + unlink(recoveryPath); /* ignore any error */ + + /* + * If we are establishing a new timeline, we have to copy data from + * the last WAL segment of the old timeline to create a starting WAL + * segment for the new timeline. + */ + if (endTLI != ThisTimeLineID) + XLogFileCopy(endLogId, endLogSeg, + endTLI, endLogId, endLogSeg); + } + + /* + * Let's just make real sure there are not .ready or .done flags posted + * for the new segment. + */ + XLogFileName(xlogpath, ThisTimeLineID, endLogId, endLogSeg); + XLogArchiveCleanup(xlogpath); + + /* Get rid of any remaining recovered timeline-history file, too */ + snprintf(recoveryPath, MAXPGPATH, XLOGDIR "/RECOVERYHISTORY"); + unlink(recoveryPath); /* ignore any error */ + + /* + * Rename the config file out of the way, so that we don't accidentally + * re-enter archive recovery mode in a subsequent crash. + */ + unlink(RECOVERY_COMMAND_DONE); + if (rename(RECOVERY_COMMAND_FILE, RECOVERY_COMMAND_DONE) != 0) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\": %m", + RECOVERY_COMMAND_FILE, RECOVERY_COMMAND_DONE))); + + ereport(LOG, + (errmsg("archive recovery complete"))); + } + + /* + * For point-in-time recovery, this function decides whether we want to + * stop applying the XLOG at or after the current record. + * + * Returns TRUE if we are stopping, FALSE otherwise. On TRUE return, + * *includeThis is set TRUE if we should apply this record before stopping. + * + * We also track the timestamp of the latest applied COMMIT/ABORT record + * in recoveryLastXTime, for logging purposes. + * Also, some information is saved in recoveryStopXid et al for use in + * annotating the new timeline's history file. + */ + static bool + recoveryStopsHere(XLogRecord *record, bool *includeThis) + { + bool stopsHere; + uint8 record_info; + TimestampTz recordXtime; + + /* We only consider stopping at COMMIT or ABORT records */ + if (record->xl_rmid != RM_XACT_ID) + return false; + record_info = record->xl_info & ~XLR_INFO_MASK; + if (record_info == XLOG_XACT_COMMIT) + { + xl_xact_commit *recordXactCommitData; + + recordXactCommitData = (xl_xact_commit *) XLogRecGetData(record); + recordXtime = recordXactCommitData->xact_time; + } + else if (record_info == XLOG_XACT_ABORT) + { + xl_xact_abort *recordXactAbortData; + + recordXactAbortData = (xl_xact_abort *) XLogRecGetData(record); + recordXtime = recordXactAbortData->xact_time; + } + else + return false; + + /* Do we have a PITR target at all? */ + if (!recoveryTarget) + { + recoveryLastXTime = recordXtime; + return false; + } + + if (recoveryTargetExact) + { + /* + * there can be only one transaction end record with this exact + * transactionid + * + * when testing for an xid, we MUST test for equality only, since + * transactions are numbered in the order they start, not the order + * they complete. A higher numbered xid will complete before you about + * 50% of the time... + */ + stopsHere = (record->xl_xid == recoveryTargetXid); + if (stopsHere) + *includeThis = recoveryTargetInclusive; + } + else + { + /* + * there can be many transactions that share the same commit time, so + * we stop after the last one, if we are inclusive, or stop at the + * first one if we are exclusive + */ + if (recoveryTargetInclusive) + stopsHere = (recordXtime > recoveryTargetTime); + else + stopsHere = (recordXtime >= recoveryTargetTime); + if (stopsHere) + *includeThis = false; + } + + if (stopsHere) + { + recoveryStopXid = record->xl_xid; + recoveryStopTime = recordXtime; + recoveryStopAfter = *includeThis; + + if (record_info == XLOG_XACT_COMMIT) + { + if (recoveryStopAfter) + ereport(LOG, + (errmsg("recovery stopping after commit of transaction %u, time %s", + recoveryStopXid, + timestamptz_to_str(recoveryStopTime)))); + else + ereport(LOG, + (errmsg("recovery stopping before commit of transaction %u, time %s", + recoveryStopXid, + timestamptz_to_str(recoveryStopTime)))); + } + else + { + if (recoveryStopAfter) + ereport(LOG, + (errmsg("recovery stopping after abort of transaction %u, time %s", + recoveryStopXid, + timestamptz_to_str(recoveryStopTime)))); + else + ereport(LOG, + (errmsg("recovery stopping before abort of transaction %u, time %s", + recoveryStopXid, + timestamptz_to_str(recoveryStopTime)))); + } + + if (recoveryStopAfter) + recoveryLastXTime = recordXtime; + } + else + recoveryLastXTime = recordXtime; + + return stopsHere; + } + + /* + * This must be called ONCE during postmaster or standalone-backend startup + */ + void + StartupXLOG(void) + { + XLogCtlInsert *Insert; + CheckPoint checkPoint; + bool wasShutdown; + bool reachedStopPoint = false; + bool haveBackupLabel = false; + XLogRecPtr RecPtr, + LastRec, + checkPointLoc, + minRecoveryLoc, + EndOfLog; + uint32 endLogId; + uint32 endLogSeg; + XLogRecord *record; + uint32 freespace; + TransactionId oldestActiveXID; + + /* + * Read control file and check XLOG status looks valid. + * + * Note: in most control paths, *ControlFile is already valid and we need + * not do ReadControlFile() here, but might as well do it to be sure. + */ + ReadControlFile(); + + if (ControlFile->state < DB_SHUTDOWNED || + ControlFile->state > DB_IN_PRODUCTION || + !XRecOffIsValid(ControlFile->checkPoint.xrecoff)) + ereport(FATAL, + (errmsg("control file contains invalid data"))); + + if (ControlFile->state == DB_SHUTDOWNED) + ereport(LOG, + (errmsg("database system was shut down at %s", + str_time(ControlFile->time)))); + else if (ControlFile->state == DB_SHUTDOWNING) + ereport(LOG, + (errmsg("database system shutdown was interrupted; last known up at %s", + str_time(ControlFile->time)))); + else if (ControlFile->state == DB_IN_CRASH_RECOVERY) + ereport(LOG, + (errmsg("database system was interrupted while in recovery at %s", + str_time(ControlFile->time)), + errhint("This probably means that some data is corrupted and" + " you will have to use the last backup for recovery."))); + else if (ControlFile->state == DB_IN_ARCHIVE_RECOVERY) + ereport(LOG, + (errmsg("database system was interrupted while in recovery at log time %s", + str_time(ControlFile->checkPointCopy.time)), + errhint("If this has occurred more than once some data might be corrupted" + " and you might need to choose an earlier recovery target."))); + else if (ControlFile->state == DB_IN_PRODUCTION) + ereport(LOG, + (errmsg("database system was interrupted; last known up at %s", + str_time(ControlFile->time)))); + + /* This is just to allow attaching to startup process with a debugger */ + #ifdef XLOG_REPLAY_DELAY + if (ControlFile->state != DB_SHUTDOWNED) + pg_usleep(60000000L); + #endif + + /* + * Verify that pg_xlog and pg_xlog/archive_status exist. In cases where + * someone has performed a copy for PITR, these directories may have + * been excluded and need to be re-created. + */ + ValidateXLOGDirectoryStructure(); + + /* + * Initialize on the assumption we want to recover to the same timeline + * that's active according to pg_control. + */ + recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID; + + /* + * Check for recovery control file, and if so set up state for offline + * recovery + */ + readRecoveryCommandFile(); + + /* Now we can determine the list of expected TLIs */ + expectedTLIs = readTimeLineHistory(recoveryTargetTLI); + + /* + * If pg_control's timeline is not in expectedTLIs, then we cannot + * proceed: the backup is not part of the history of the requested + * timeline. + */ + if (!list_member_int(expectedTLIs, + (int) ControlFile->checkPointCopy.ThisTimeLineID)) + ereport(FATAL, + (errmsg("requested timeline %u is not a child of database system timeline %u", + recoveryTargetTLI, + ControlFile->checkPointCopy.ThisTimeLineID))); + + if (read_backup_label(&checkPointLoc, &minRecoveryLoc)) + { + /* + * When a backup_label file is present, we want to roll forward from + * the checkpoint it identifies, rather than using pg_control. + */ + record = ReadCheckpointRecord(checkPointLoc, 0); + if (record != NULL) + { + ereport(DEBUG1, + (errmsg("checkpoint record is at %X/%X", + checkPointLoc.xlogid, checkPointLoc.xrecoff))); + InRecovery = true; /* force recovery even if SHUTDOWNED */ + } + else + { + ereport(PANIC, + (errmsg("could not locate required checkpoint record"), + errhint("If you are not restoring from a backup, try removing the file \"%s/backup_label\".", DataDir))); + } + /* set flag to delete it later */ + haveBackupLabel = true; + } + else + { + /* + * Get the last valid checkpoint record. If the latest one according + * to pg_control is broken, try the next-to-last one. + */ + checkPointLoc = ControlFile->checkPoint; + record = ReadCheckpointRecord(checkPointLoc, 1); + if (record != NULL) + { + ereport(DEBUG1, + (errmsg("checkpoint record is at %X/%X", + checkPointLoc.xlogid, checkPointLoc.xrecoff))); + } + else + { + checkPointLoc = ControlFile->prevCheckPoint; + record = ReadCheckpointRecord(checkPointLoc, 2); + if (record != NULL) + { + ereport(LOG, + (errmsg("using previous checkpoint record at %X/%X", + checkPointLoc.xlogid, checkPointLoc.xrecoff))); + InRecovery = true; /* force recovery even if SHUTDOWNED */ + } + else + ereport(PANIC, + (errmsg("could not locate a valid checkpoint record"))); + } + } + + LastRec = RecPtr = checkPointLoc; + memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint)); + wasShutdown = (record->xl_info == XLOG_CHECKPOINT_SHUTDOWN); + + ereport(DEBUG1, + (errmsg("redo record is at %X/%X; shutdown %s", + checkPoint.redo.xlogid, checkPoint.redo.xrecoff, + wasShutdown ? "TRUE" : "FALSE"))); + ereport(DEBUG1, + (errmsg("next transaction ID: %u/%u; next OID: %u", + checkPoint.nextXidEpoch, checkPoint.nextXid, + checkPoint.nextOid))); + ereport(DEBUG1, + (errmsg("next MultiXactId: %u; next MultiXactOffset: %u", + checkPoint.nextMulti, checkPoint.nextMultiOffset))); + if (!TransactionIdIsNormal(checkPoint.nextXid)) + ereport(PANIC, + (errmsg("invalid next transaction ID"))); + + ShmemVariableCache->nextXid = checkPoint.nextXid; + ShmemVariableCache->nextOid = checkPoint.nextOid; + ShmemVariableCache->oidCount = 0; + MultiXactSetNextMXact(checkPoint.nextMulti, checkPoint.nextMultiOffset); + + /* + * We must replay WAL entries using the same TimeLineID they were created + * under, so temporarily adopt the TLI indicated by the checkpoint (see + * also xlog_redo()). + */ + ThisTimeLineID = checkPoint.ThisTimeLineID; + + RedoRecPtr = XLogCtl->Insert.RedoRecPtr = checkPoint.redo; + + if (XLByteLT(RecPtr, checkPoint.redo)) + ereport(PANIC, + (errmsg("invalid redo in checkpoint record"))); + + /* + * Check whether we need to force recovery from WAL. If it appears to + * have been a clean shutdown and we did not have a recovery.conf file, + * then assume no recovery needed. + */ + if (XLByteLT(checkPoint.redo, RecPtr)) + { + if (wasShutdown) + ereport(PANIC, + (errmsg("invalid redo record in shutdown checkpoint"))); + InRecovery = true; + } + else if (ControlFile->state != DB_SHUTDOWNED) + InRecovery = true; + else if (InArchiveRecovery) + { + /* force recovery due to presence of recovery.conf */ + InRecovery = true; + } + + /* REDO */ + if (InRecovery) + { + int rmid; + + /* + * Update pg_control to show that we are recovering and to show the + * selected checkpoint as the place we are starting from. We also mark + * pg_control with any minimum recovery stop point obtained from a + * backup history file. + */ + if (InArchiveRecovery) + { + ereport(LOG, + (errmsg("automatic recovery in progress"))); + ControlFile->state = DB_IN_ARCHIVE_RECOVERY; + } + else + { + ereport(LOG, + (errmsg("database system was not properly shut down; " + "automatic recovery in progress"))); + ControlFile->state = DB_IN_CRASH_RECOVERY; + } + ControlFile->prevCheckPoint = ControlFile->checkPoint; + ControlFile->checkPoint = checkPointLoc; + ControlFile->checkPointCopy = checkPoint; + if (minRecoveryLoc.xlogid != 0 || minRecoveryLoc.xrecoff != 0) + ControlFile->minRecoveryPoint = minRecoveryLoc; + ControlFile->time = (pg_time_t) time(NULL); + UpdateControlFile(); + + /* + * If there was a backup label file, it's done its job and the info + * has now been propagated into pg_control. We must get rid of the + * label file so that if we crash during recovery, we'll pick up at + * the latest recovery restartpoint instead of going all the way back + * to the backup start point. It seems prudent though to just rename + * the file out of the way rather than delete it completely. + */ + if (haveBackupLabel) + { + unlink(BACKUP_LABEL_OLD); + if (rename(BACKUP_LABEL_FILE, BACKUP_LABEL_OLD) != 0) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\": %m", + BACKUP_LABEL_FILE, BACKUP_LABEL_OLD))); + } + + /* Initialize resource managers */ + for (rmid = 0; rmid <= RM_MAX_ID; rmid++) + { + if (RmgrTable[rmid].rm_startup != NULL) + RmgrTable[rmid].rm_startup(); + } + + /* + * Find the first record that logically follows the checkpoint --- it + * might physically precede it, though. + */ + if (XLByteLT(checkPoint.redo, RecPtr)) + { + /* back up to find the record */ + record = ReadRecord(&(checkPoint.redo), PANIC); + } + else + { + /* just have to read next record after CheckPoint */ + record = ReadRecord(NULL, LOG); + } + + if (record != NULL) + { + bool recoveryContinue = true; + bool recoveryApply = true; + ErrorContextCallback errcontext; + + InRedo = true; + ereport(LOG, + (errmsg("redo starts at %X/%X", + ReadRecPtr.xlogid, ReadRecPtr.xrecoff))); + + /* + * main redo apply loop + */ + do + { + #ifdef WAL_DEBUG + if (XLOG_DEBUG) + { + StringInfoData buf; + + initStringInfo(&buf); + appendStringInfo(&buf, "REDO @ %X/%X; LSN %X/%X: ", + ReadRecPtr.xlogid, ReadRecPtr.xrecoff, + EndRecPtr.xlogid, EndRecPtr.xrecoff); + xlog_outrec(&buf, record); + appendStringInfo(&buf, " - "); + RmgrTable[record->xl_rmid].rm_desc(&buf, + record->xl_info, + XLogRecGetData(record)); + elog(LOG, "%s", buf.data); + pfree(buf.data); + } + #endif + + /* + * Have we reached our recovery target? + */ + if (recoveryStopsHere(record, &recoveryApply)) + { + reachedStopPoint = true; /* see below */ + recoveryContinue = false; + if (!recoveryApply) + break; + } + + /* Setup error traceback support for ereport() */ + errcontext.callback = rm_redo_error_callback; + errcontext.arg = (void *) record; + errcontext.previous = error_context_stack; + error_context_stack = &errcontext; + + /* nextXid must be beyond record's xid */ + if (TransactionIdFollowsOrEquals(record->xl_xid, + ShmemVariableCache->nextXid)) + { + ShmemVariableCache->nextXid = record->xl_xid; + TransactionIdAdvance(ShmemVariableCache->nextXid); + } + + RmgrTable[record->xl_rmid].rm_redo(EndRecPtr, record); + + /* Pop the error context stack */ + error_context_stack = errcontext.previous; + + LastRec = ReadRecPtr; + + record = ReadRecord(NULL, LOG); + } while (record != NULL && recoveryContinue); + + /* + * end of main redo apply loop + */ + + ereport(LOG, + (errmsg("redo done at %X/%X", + ReadRecPtr.xlogid, ReadRecPtr.xrecoff))); + if (recoveryLastXTime) + ereport(LOG, + (errmsg("last completed transaction was at log time %s", + timestamptz_to_str(recoveryLastXTime)))); + InRedo = false; + } + else + { + /* there are no WAL records following the checkpoint */ + ereport(LOG, + (errmsg("redo is not required"))); + } + } + + /* + * Re-fetch the last valid or last applied record, so we can identify the + * exact endpoint of what we consider the valid portion of WAL. + */ + record = ReadRecord(&LastRec, PANIC); + EndOfLog = EndRecPtr; + XLByteToPrevSeg(EndOfLog, endLogId, endLogSeg); + + /* + * Complain if we did not roll forward far enough to render the backup + * dump consistent. + */ + if (XLByteLT(EndOfLog, ControlFile->minRecoveryPoint)) + { + if (reachedStopPoint) /* stopped because of stop request */ + ereport(FATAL, + (errmsg("requested recovery stop point is before end time of backup dump"))); + else /* ran off end of WAL */ + ereport(FATAL, + (errmsg("WAL ends before end time of backup dump"))); + } + + /* + * Consider whether we need to assign a new timeline ID. + * + * If we are doing an archive recovery, we always assign a new ID. This + * handles a couple of issues. If we stopped short of the end of WAL + * during recovery, then we are clearly generating a new timeline and must + * assign it a unique new ID. Even if we ran to the end, modifying the + * current last segment is problematic because it may result in trying to + * overwrite an already-archived copy of that segment, and we encourage + * DBAs to make their archive_commands reject that. We can dodge the + * problem by making the new active segment have a new timeline ID. + * + * In a normal crash recovery, we can just extend the timeline we were in. + */ + if (InArchiveRecovery) + { + ThisTimeLineID = findNewestTimeLine(recoveryTargetTLI) + 1; + ereport(LOG, + (errmsg("selected new timeline ID: %u", ThisTimeLineID))); + writeTimeLineHistory(ThisTimeLineID, recoveryTargetTLI, + curFileTLI, endLogId, endLogSeg); + } + + /* Save the selected TimeLineID in shared memory, too */ + XLogCtl->ThisTimeLineID = ThisTimeLineID; + + /* + * We are now done reading the old WAL. Turn off archive fetching if it + * was active, and make a writable copy of the last WAL segment. (Note + * that we also have a copy of the last block of the old WAL in readBuf; + * we will use that below.) + */ + if (InArchiveRecovery) + exitArchiveRecovery(curFileTLI, endLogId, endLogSeg); + + /* + * Prepare to write WAL starting at EndOfLog position, and init xlog + * buffer cache using the block containing the last record from the + * previous incarnation. + */ + openLogId = endLogId; + openLogSeg = endLogSeg; + openLogFile = XLogFileOpen(openLogId, openLogSeg); + openLogOff = 0; + Insert = &XLogCtl->Insert; + Insert->PrevRecord = LastRec; + XLogCtl->xlblocks[0].xlogid = openLogId; + XLogCtl->xlblocks[0].xrecoff = + ((EndOfLog.xrecoff - 1) / XLOG_BLCKSZ + 1) * XLOG_BLCKSZ; + + /* + * Tricky point here: readBuf contains the *last* block that the LastRec + * record spans, not the one it starts in. The last block is indeed the + * one we want to use. + */ + Assert(readOff == (XLogCtl->xlblocks[0].xrecoff - XLOG_BLCKSZ) % XLogSegSize); + memcpy((char *) Insert->currpage, readBuf, XLOG_BLCKSZ); + Insert->currpos = (char *) Insert->currpage + + (EndOfLog.xrecoff + XLOG_BLCKSZ - XLogCtl->xlblocks[0].xrecoff); + + LogwrtResult.Write = LogwrtResult.Flush = EndOfLog; + + XLogCtl->Write.LogwrtResult = LogwrtResult; + Insert->LogwrtResult = LogwrtResult; + XLogCtl->LogwrtResult = LogwrtResult; + + XLogCtl->LogwrtRqst.Write = EndOfLog; + XLogCtl->LogwrtRqst.Flush = EndOfLog; + + freespace = INSERT_FREESPACE(Insert); + if (freespace > 0) + { + /* Make sure rest of page is zero */ + MemSet(Insert->currpos, 0, freespace); + XLogCtl->Write.curridx = 0; + } + else + { + /* + * Whenever Write.LogwrtResult points to exactly the end of a page, + * Write.curridx must point to the *next* page (see XLogWrite()). + * + * Note: it might seem we should do AdvanceXLInsertBuffer() here, but + * this is sufficient. The first actual attempt to insert a log + * record will advance the insert state. + */ + XLogCtl->Write.curridx = NextBufIdx(0); + } + + /* Pre-scan prepared transactions to find out the range of XIDs present */ + oldestActiveXID = PrescanPreparedTransactions(); + + if (InRecovery) + { + int rmid; + + /* + * Allow resource managers to do any required cleanup. + */ + for (rmid = 0; rmid <= RM_MAX_ID; rmid++) + { + if (RmgrTable[rmid].rm_cleanup != NULL) + RmgrTable[rmid].rm_cleanup(); + } + + /* + * Check to see if the XLOG sequence contained any unresolved + * references to uninitialized pages. + */ + XLogCheckInvalidPages(); + + /* + * Reset pgstat data, because it may be invalid after recovery. + */ + pgstat_reset_all(); + + /* + * Perform a checkpoint to update all our recovery activity to disk. + * + * Note that we write a shutdown checkpoint rather than an on-line + * one. This is not particularly critical, but since we may be + * assigning a new TLI, using a shutdown checkpoint allows us to have + * the rule that TLI only changes in shutdown checkpoints, which + * allows some extra error checking in xlog_redo. + */ + CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE); + } + + /* + * Preallocate additional log files, if wanted. + */ + PreallocXlogFiles(EndOfLog); + + /* + * Okay, we're officially UP. + */ + InRecovery = false; + + ControlFile->state = DB_IN_PRODUCTION; + ControlFile->time = (pg_time_t) time(NULL); + UpdateControlFile(); + + /* start the archive_timeout timer running */ + XLogCtl->Write.lastSegSwitchTime = ControlFile->time; + + /* initialize shared-memory copy of latest checkpoint XID/epoch */ + XLogCtl->ckptXidEpoch = ControlFile->checkPointCopy.nextXidEpoch; + XLogCtl->ckptXid = ControlFile->checkPointCopy.nextXid; + + /* also initialize latestCompletedXid, to nextXid - 1 */ + ShmemVariableCache->latestCompletedXid = ShmemVariableCache->nextXid; + TransactionIdRetreat(ShmemVariableCache->latestCompletedXid); + + /* Start up the commit log and related stuff, too */ + StartupCLOG(); + StartupSUBTRANS(oldestActiveXID); + StartupMultiXact(); + + /* Reload shared-memory state for prepared transactions */ + RecoverPreparedTransactions(); + + /* Shut down readFile facility, free space */ + if (readFile >= 0) + { + close(readFile); + readFile = -1; + } + if (readBuf) + { + free(readBuf); + readBuf = NULL; + } + if (readRecordBuf) + { + free(readRecordBuf); + readRecordBuf = NULL; + readRecordBufSize = 0; + } + } + + /* + * Subroutine to try to fetch and validate a prior checkpoint record. + * + * whichChkpt identifies the checkpoint (merely for reporting purposes). + * 1 for "primary", 2 for "secondary", 0 for "other" (backup_label) + */ + static XLogRecord * + ReadCheckpointRecord(XLogRecPtr RecPtr, int whichChkpt) + { + XLogRecord *record; + + if (!XRecOffIsValid(RecPtr.xrecoff)) + { + switch (whichChkpt) + { + case 1: + ereport(LOG, + (errmsg("invalid primary checkpoint link in control file"))); + break; + case 2: + ereport(LOG, + (errmsg("invalid secondary checkpoint link in control file"))); + break; + default: + ereport(LOG, + (errmsg("invalid checkpoint link in backup_label file"))); + break; + } + return NULL; + } + + record = ReadRecord(&RecPtr, LOG); + + if (record == NULL) + { + switch (whichChkpt) + { + case 1: + ereport(LOG, + (errmsg("invalid primary checkpoint record"))); + break; + case 2: + ereport(LOG, + (errmsg("invalid secondary checkpoint record"))); + break; + default: + ereport(LOG, + (errmsg("invalid checkpoint record"))); + break; + } + return NULL; + } + if (record->xl_rmid != RM_XLOG_ID) + { + switch (whichChkpt) + { + case 1: + ereport(LOG, + (errmsg("invalid resource manager ID in primary checkpoint record"))); + break; + case 2: + ereport(LOG, + (errmsg("invalid resource manager ID in secondary checkpoint record"))); + break; + default: + ereport(LOG, + (errmsg("invalid resource manager ID in checkpoint record"))); + break; + } + return NULL; + } + if (record->xl_info != XLOG_CHECKPOINT_SHUTDOWN && + record->xl_info != XLOG_CHECKPOINT_ONLINE) + { + switch (whichChkpt) + { + case 1: + ereport(LOG, + (errmsg("invalid xl_info in primary checkpoint record"))); + break; + case 2: + ereport(LOG, + (errmsg("invalid xl_info in secondary checkpoint record"))); + break; + default: + ereport(LOG, + (errmsg("invalid xl_info in checkpoint record"))); + break; + } + return NULL; + } + if (record->xl_len != sizeof(CheckPoint) || + record->xl_tot_len != SizeOfXLogRecord + sizeof(CheckPoint)) + { + switch (whichChkpt) + { + case 1: + ereport(LOG, + (errmsg("invalid length of primary checkpoint record"))); + break; + case 2: + ereport(LOG, + (errmsg("invalid length of secondary checkpoint record"))); + break; + default: + ereport(LOG, + (errmsg("invalid length of checkpoint record"))); + break; + } + return NULL; + } + return record; + } + + /* + * This must be called during startup of a backend process, except that + * it need not be called in a standalone backend (which does StartupXLOG + * instead). We need to initialize the local copies of ThisTimeLineID and + * RedoRecPtr. + * + * Note: before Postgres 8.0, we went to some effort to keep the postmaster + * process's copies of ThisTimeLineID and RedoRecPtr valid too. This was + * unnecessary however, since the postmaster itself never touches XLOG anyway. + */ + void + InitXLOGAccess(void) + { + /* ThisTimeLineID doesn't change so we need no lock to copy it */ + ThisTimeLineID = XLogCtl->ThisTimeLineID; + /* Use GetRedoRecPtr to copy the RedoRecPtr safely */ + (void) GetRedoRecPtr(); + } + + /* + * Once spawned, a backend may update its local RedoRecPtr from + * XLogCtl->Insert.RedoRecPtr; it must hold the insert lock or info_lck + * to do so. This is done in XLogInsert() or GetRedoRecPtr(). + */ + XLogRecPtr + GetRedoRecPtr(void) + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + Assert(XLByteLE(RedoRecPtr, xlogctl->Insert.RedoRecPtr)); + RedoRecPtr = xlogctl->Insert.RedoRecPtr; + SpinLockRelease(&xlogctl->info_lck); + + return RedoRecPtr; + } + + /* + * GetInsertRecPtr -- Returns the current insert position. + * + * NOTE: The value *actually* returned is the position of the last full + * xlog page. It lags behind the real insert position by at most 1 page. + * For that, we don't need to acquire WALInsertLock which can be quite + * heavily contended, and an approximation is enough for the current + * usage of this function. + */ + XLogRecPtr + GetInsertRecPtr(void) + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + XLogRecPtr recptr; + + SpinLockAcquire(&xlogctl->info_lck); + recptr = xlogctl->LogwrtRqst.Write; + SpinLockRelease(&xlogctl->info_lck); + + return recptr; + } + + /* + * Get the time of the last xlog segment switch + */ + pg_time_t + GetLastSegSwitchTime(void) + { + pg_time_t result; + + /* Need WALWriteLock, but shared lock is sufficient */ + LWLockAcquire(WALWriteLock, LW_SHARED); + result = XLogCtl->Write.lastSegSwitchTime; + LWLockRelease(WALWriteLock); + + return result; + } + + /* + * GetNextXidAndEpoch - get the current nextXid value and associated epoch + * + * This is exported for use by code that would like to have 64-bit XIDs. + * We don't really support such things, but all XIDs within the system + * can be presumed "close to" the result, and thus the epoch associated + * with them can be determined. + */ + void + GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch) + { + uint32 ckptXidEpoch; + TransactionId ckptXid; + TransactionId nextXid; + + /* Must read checkpoint info first, else have race condition */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + ckptXidEpoch = xlogctl->ckptXidEpoch; + ckptXid = xlogctl->ckptXid; + SpinLockRelease(&xlogctl->info_lck); + } + + /* Now fetch current nextXid */ + nextXid = ReadNewTransactionId(); + + /* + * nextXid is certainly logically later than ckptXid. So if it's + * numerically less, it must have wrapped into the next epoch. + */ + if (nextXid < ckptXid) + ckptXidEpoch++; + + *xid = nextXid; + *epoch = ckptXidEpoch; + } + + /* + * This must be called ONCE during postmaster or standalone-backend shutdown + */ + void + ShutdownXLOG(int code, Datum arg) + { + ereport(LOG, + (errmsg("shutting down"))); + + CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE); + ShutdownCLOG(); + ShutdownSUBTRANS(); + ShutdownMultiXact(); + + ereport(LOG, + (errmsg("database system is shut down"))); + } + + /* + * Log start of a checkpoint. + */ + static void + LogCheckpointStart(int flags) + { + elog(LOG, "checkpoint starting:%s%s%s%s%s%s", + (flags & CHECKPOINT_IS_SHUTDOWN) ? " shutdown" : "", + (flags & CHECKPOINT_IMMEDIATE) ? " immediate" : "", + (flags & CHECKPOINT_FORCE) ? " force" : "", + (flags & CHECKPOINT_WAIT) ? " wait" : "", + (flags & CHECKPOINT_CAUSE_XLOG) ? " xlog" : "", + (flags & CHECKPOINT_CAUSE_TIME) ? " time" : ""); + } + + /* + * Log end of a checkpoint. + */ + static void + LogCheckpointEnd(void) + { + long write_secs, + sync_secs, + total_secs; + int write_usecs, + sync_usecs, + total_usecs; + + CheckpointStats.ckpt_end_t = GetCurrentTimestamp(); + + TimestampDifference(CheckpointStats.ckpt_start_t, + CheckpointStats.ckpt_end_t, + &total_secs, &total_usecs); + + TimestampDifference(CheckpointStats.ckpt_write_t, + CheckpointStats.ckpt_sync_t, + &write_secs, &write_usecs); + + TimestampDifference(CheckpointStats.ckpt_sync_t, + CheckpointStats.ckpt_sync_end_t, + &sync_secs, &sync_usecs); + + elog(LOG, "checkpoint complete: wrote %d buffers (%.1f%%); " + "%d transaction log file(s) added, %d removed, %d recycled; " + "write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s", + CheckpointStats.ckpt_bufs_written, + (double) CheckpointStats.ckpt_bufs_written * 100 / NBuffers, + CheckpointStats.ckpt_segs_added, + CheckpointStats.ckpt_segs_removed, + CheckpointStats.ckpt_segs_recycled, + write_secs, write_usecs / 1000, + sync_secs, sync_usecs / 1000, + total_secs, total_usecs / 1000); + } + + /* + * Perform a checkpoint --- either during shutdown, or on-the-fly + * + * flags is a bitwise OR of the following: + * CHECKPOINT_IS_SHUTDOWN: checkpoint is for database shutdown. + * CHECKPOINT_IMMEDIATE: finish the checkpoint ASAP, + * ignoring checkpoint_completion_target parameter. + * CHECKPOINT_FORCE: force a checkpoint even if no XLOG activity has occured + * since the last one (implied by CHECKPOINT_IS_SHUTDOWN). + * + * Note: flags contains other bits, of interest here only for logging purposes. + * In particular note that this routine is synchronous and does not pay + * attention to CHECKPOINT_WAIT. + */ + void + CreateCheckPoint(int flags) + { + bool shutdown = (flags & CHECKPOINT_IS_SHUTDOWN) != 0; + CheckPoint checkPoint; + XLogRecPtr recptr; + XLogCtlInsert *Insert = &XLogCtl->Insert; + XLogRecData rdata; + uint32 freespace; + uint32 _logId; + uint32 _logSeg; + TransactionId *inCommitXids; + int nInCommit; + + /* + * Acquire CheckpointLock to ensure only one checkpoint happens at a time. + * (This is just pro forma, since in the present system structure there is + * only one process that is allowed to issue checkpoints at any given + * time.) + */ + LWLockAcquire(CheckpointLock, LW_EXCLUSIVE); + + /* + * Prepare to accumulate statistics. + * + * Note: because it is possible for log_checkpoints to change while a + * checkpoint proceeds, we always accumulate stats, even if + * log_checkpoints is currently off. + */ + MemSet(&CheckpointStats, 0, sizeof(CheckpointStats)); + CheckpointStats.ckpt_start_t = GetCurrentTimestamp(); + + /* + * Use a critical section to force system panic if we have trouble. + */ + START_CRIT_SECTION(); + + if (shutdown) + { + ControlFile->state = DB_SHUTDOWNING; + ControlFile->time = (pg_time_t) time(NULL); + UpdateControlFile(); + } + + /* + * Let smgr prepare for checkpoint; this has to happen before we determine + * the REDO pointer. Note that smgr must not do anything that'd have to + * be undone if we decide no checkpoint is needed. + */ + smgrpreckpt(); + + /* Begin filling in the checkpoint WAL record */ + MemSet(&checkPoint, 0, sizeof(checkPoint)); + checkPoint.ThisTimeLineID = ThisTimeLineID; + checkPoint.time = (pg_time_t) time(NULL); + + /* + * We must hold WALInsertLock while examining insert state to determine + * the checkpoint REDO pointer. + */ + LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); + + /* + * If this isn't a shutdown or forced checkpoint, and we have not inserted + * any XLOG records since the start of the last checkpoint, skip the + * checkpoint. The idea here is to avoid inserting duplicate checkpoints + * when the system is idle. That wastes log space, and more importantly it + * exposes us to possible loss of both current and previous checkpoint + * records if the machine crashes just as we're writing the update. + * (Perhaps it'd make even more sense to checkpoint only when the previous + * checkpoint record is in a different xlog page?) + * + * We have to make two tests to determine that nothing has happened since + * the start of the last checkpoint: current insertion point must match + * the end of the last checkpoint record, and its redo pointer must point + * to itself. + */ + if ((flags & (CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_FORCE)) == 0) + { + XLogRecPtr curInsert; + + INSERT_RECPTR(curInsert, Insert, Insert->curridx); + if (curInsert.xlogid == ControlFile->checkPoint.xlogid && + curInsert.xrecoff == ControlFile->checkPoint.xrecoff + + MAXALIGN(SizeOfXLogRecord + sizeof(CheckPoint)) && + ControlFile->checkPoint.xlogid == + ControlFile->checkPointCopy.redo.xlogid && + ControlFile->checkPoint.xrecoff == + ControlFile->checkPointCopy.redo.xrecoff) + { + LWLockRelease(WALInsertLock); + LWLockRelease(CheckpointLock); + END_CRIT_SECTION(); + return; + } + } + + /* + * Compute new REDO record ptr = location of next XLOG record. + * + * NB: this is NOT necessarily where the checkpoint record itself will be, + * since other backends may insert more XLOG records while we're off doing + * the buffer flush work. Those XLOG records are logically after the + * checkpoint, even though physically before it. Got that? + */ + freespace = INSERT_FREESPACE(Insert); + if (freespace < SizeOfXLogRecord) + { + (void) AdvanceXLInsertBuffer(false); + /* OK to ignore update return flag, since we will do flush anyway */ + freespace = INSERT_FREESPACE(Insert); + } + INSERT_RECPTR(checkPoint.redo, Insert, Insert->curridx); + + /* + * Here we update the shared RedoRecPtr for future XLogInsert calls; this + * must be done while holding the insert lock AND the info_lck. + * + * Note: if we fail to complete the checkpoint, RedoRecPtr will be left + * pointing past where it really needs to point. This is okay; the only + * consequence is that XLogInsert might back up whole buffers that it + * didn't really need to. We can't postpone advancing RedoRecPtr because + * XLogInserts that happen while we are dumping buffers must assume that + * their buffer changes are not included in the checkpoint. + */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + RedoRecPtr = xlogctl->Insert.RedoRecPtr = checkPoint.redo; + SpinLockRelease(&xlogctl->info_lck); + } + + /* + * Now we can release WAL insert lock, allowing other xacts to proceed + * while we are flushing disk buffers. + */ + LWLockRelease(WALInsertLock); + + /* + * If enabled, log checkpoint start. We postpone this until now so as not + * to log anything if we decided to skip the checkpoint. + */ + if (log_checkpoints) + LogCheckpointStart(flags); + + TRACE_POSTGRESQL_CHECKPOINT_START(flags); + + /* + * Before flushing data, we must wait for any transactions that are + * currently in their commit critical sections. If an xact inserted its + * commit record into XLOG just before the REDO point, then a crash + * restart from the REDO point would not replay that record, which means + * that our flushing had better include the xact's update of pg_clog. So + * we wait till he's out of his commit critical section before proceeding. + * See notes in RecordTransactionCommit(). + * + * Because we've already released WALInsertLock, this test is a bit fuzzy: + * it is possible that we will wait for xacts we didn't really need to + * wait for. But the delay should be short and it seems better to make + * checkpoint take a bit longer than to hold locks longer than necessary. + * (In fact, the whole reason we have this issue is that xact.c does + * commit record XLOG insertion and clog update as two separate steps + * protected by different locks, but again that seems best on grounds of + * minimizing lock contention.) + * + * A transaction that has not yet set inCommit when we look cannot be at + * risk, since he's not inserted his commit record yet; and one that's + * already cleared it is not at risk either, since he's done fixing clog + * and we will correctly flush the update below. So we cannot miss any + * xacts we need to wait for. + */ + nInCommit = GetTransactionsInCommit(&inCommitXids); + if (nInCommit > 0) + { + do + { + pg_usleep(10000L); /* wait for 10 msec */ + } while (HaveTransactionsInCommit(inCommitXids, nInCommit)); + } + pfree(inCommitXids); + + /* + * Get the other info we need for the checkpoint record. + */ + LWLockAcquire(XidGenLock, LW_SHARED); + checkPoint.nextXid = ShmemVariableCache->nextXid; + LWLockRelease(XidGenLock); + + /* Increase XID epoch if we've wrapped around since last checkpoint */ + checkPoint.nextXidEpoch = ControlFile->checkPointCopy.nextXidEpoch; + if (checkPoint.nextXid < ControlFile->checkPointCopy.nextXid) + checkPoint.nextXidEpoch++; + + LWLockAcquire(OidGenLock, LW_SHARED); + checkPoint.nextOid = ShmemVariableCache->nextOid; + if (!shutdown) + checkPoint.nextOid += ShmemVariableCache->oidCount; + LWLockRelease(OidGenLock); + + MultiXactGetCheckptMulti(shutdown, + &checkPoint.nextMulti, + &checkPoint.nextMultiOffset); + + /* + * Having constructed the checkpoint record, ensure all shmem disk buffers + * and commit-log buffers are flushed to disk. + * + * This I/O could fail for various reasons. If so, we will fail to + * complete the checkpoint, but there is no reason to force a system + * panic. Accordingly, exit critical section while doing it. + */ + END_CRIT_SECTION(); + + CheckPointGuts(checkPoint.redo, flags); + + START_CRIT_SECTION(); + + /* + * Now insert the checkpoint record into XLOG. + */ + rdata.data = (char *) (&checkPoint); + rdata.len = sizeof(checkPoint); + rdata.buffer = InvalidBuffer; + rdata.next = NULL; + + recptr = XLogInsert(RM_XLOG_ID, + shutdown ? XLOG_CHECKPOINT_SHUTDOWN : + XLOG_CHECKPOINT_ONLINE, + &rdata); + + XLogFlush(recptr); + + /* + * We now have ProcLastRecPtr = start of actual checkpoint record, recptr + * = end of actual checkpoint record. + */ + if (shutdown && !XLByteEQ(checkPoint.redo, ProcLastRecPtr)) + ereport(PANIC, + (errmsg("concurrent transaction log activity while database system is shutting down"))); + + /* + * Select point at which we can truncate the log, which we base on the + * prior checkpoint's earliest info. + */ + XLByteToSeg(ControlFile->checkPointCopy.redo, _logId, _logSeg); + + /* + * Update the control file. + */ + LWLockAcquire(ControlFileLock, LW_EXCLUSIVE); + if (shutdown) + ControlFile->state = DB_SHUTDOWNED; + ControlFile->prevCheckPoint = ControlFile->checkPoint; + ControlFile->checkPoint = ProcLastRecPtr; + ControlFile->checkPointCopy = checkPoint; + ControlFile->time = (pg_time_t) time(NULL); + UpdateControlFile(); + LWLockRelease(ControlFileLock); + + /* Update shared-memory copy of checkpoint XID/epoch */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + xlogctl->ckptXidEpoch = checkPoint.nextXidEpoch; + xlogctl->ckptXid = checkPoint.nextXid; + SpinLockRelease(&xlogctl->info_lck); + } + + /* + * We are now done with critical updates; no need for system panic if we + * have trouble while fooling with old log segments. + */ + END_CRIT_SECTION(); + + /* + * Let smgr do post-checkpoint cleanup (eg, deleting old files). + */ + smgrpostckpt(); + + /* + * Delete old log files (those no longer needed even for previous + * checkpoint). + */ + if (_logId || _logSeg) + { + PrevLogSeg(_logId, _logSeg); + RemoveOldXlogFiles(_logId, _logSeg, recptr); + } + + /* + * Make more log segments if needed. (Do this after recycling old log + * segments, since that may supply some of the needed files.) + */ + if (!shutdown) + PreallocXlogFiles(recptr); + + /* + * Truncate pg_subtrans if possible. We can throw away all data before + * the oldest XMIN of any running transaction. No future transaction will + * attempt to reference any pg_subtrans entry older than that (see Asserts + * in subtrans.c). During recovery, though, we mustn't do this because + * StartupSUBTRANS hasn't been called yet. + */ + if (!InRecovery) + TruncateSUBTRANS(GetOldestXmin(true, false)); + + /* All real work is done, but log before releasing lock. */ + if (log_checkpoints) + LogCheckpointEnd(); + + TRACE_POSTGRESQL_CHECKPOINT_DONE(CheckpointStats.ckpt_bufs_written, + NBuffers, CheckpointStats.ckpt_segs_added, + CheckpointStats.ckpt_segs_removed, + CheckpointStats.ckpt_segs_recycled); + + LWLockRelease(CheckpointLock); + } + + /* + * Flush all data in shared memory to disk, and fsync + * + * This is the common code shared between regular checkpoints and + * recovery restartpoints. + */ + static void + CheckPointGuts(XLogRecPtr checkPointRedo, int flags) + { + CheckPointCLOG(); + CheckPointSUBTRANS(); + CheckPointMultiXact(); + CheckPointBuffers(flags); /* performs all required fsyncs */ + /* We deliberately delay 2PC checkpointing as long as possible */ + CheckPointTwoPhase(checkPointRedo); + } + + /* + * Set a recovery restart point if appropriate + * + * This is similar to CreateCheckPoint, but is used during WAL recovery + * to establish a point from which recovery can roll forward without + * replaying the entire recovery log. This function is called each time + * a checkpoint record is read from XLOG; it must determine whether a + * restartpoint is needed or not. + */ + static void + RecoveryRestartPoint(const CheckPoint *checkPoint) + { + int elapsed_secs; + int rmid; + + /* + * Do nothing if the elapsed time since the last restartpoint is less than + * half of checkpoint_timeout. (We use a value less than + * checkpoint_timeout so that variations in the timing of checkpoints on + * the master, or speed of transmission of WAL segments to a slave, won't + * make the slave skip a restartpoint once it's synced with the master.) + * Checking true elapsed time keeps us from doing restartpoints too often + * while rapidly scanning large amounts of WAL. + */ + elapsed_secs = (pg_time_t) time(NULL) - ControlFile->time; + if (elapsed_secs < CheckPointTimeout / 2) + return; + + /* + * Is it safe to checkpoint? We must ask each of the resource managers + * whether they have any partial state information that might prevent a + * correct restart from this point. If so, we skip this opportunity, but + * return at the next checkpoint record for another try. + */ + for (rmid = 0; rmid <= RM_MAX_ID; rmid++) + { + if (RmgrTable[rmid].rm_safe_restartpoint != NULL) + if (!(RmgrTable[rmid].rm_safe_restartpoint())) + { + elog(DEBUG2, "RM %d not safe to record restart point at %X/%X", + rmid, + checkPoint->redo.xlogid, + checkPoint->redo.xrecoff); + return; + } + } + + /* + * OK, force data out to disk + */ + CheckPointGuts(checkPoint->redo, CHECKPOINT_IMMEDIATE); + + /* + * Update pg_control so that any subsequent crash will restart from this + * checkpoint. Note: ReadRecPtr gives the XLOG address of the checkpoint + * record itself. + */ + ControlFile->prevCheckPoint = ControlFile->checkPoint; + ControlFile->checkPoint = ReadRecPtr; + ControlFile->checkPointCopy = *checkPoint; + ControlFile->time = (pg_time_t) time(NULL); + UpdateControlFile(); + + ereport((recoveryLogRestartpoints ? LOG : DEBUG2), + (errmsg("recovery restart point at %X/%X", + checkPoint->redo.xlogid, checkPoint->redo.xrecoff))); + if (recoveryLastXTime) + ereport((recoveryLogRestartpoints ? LOG : DEBUG2), + (errmsg("last completed transaction was at log time %s", + timestamptz_to_str(recoveryLastXTime)))); + } + + /* + * Write a NEXTOID log record + */ + void + XLogPutNextOid(Oid nextOid) + { + XLogRecData rdata; + + rdata.data = (char *) (&nextOid); + rdata.len = sizeof(Oid); + rdata.buffer = InvalidBuffer; + rdata.next = NULL; + (void) XLogInsert(RM_XLOG_ID, XLOG_NEXTOID, &rdata); + + /* + * We need not flush the NEXTOID record immediately, because any of the + * just-allocated OIDs could only reach disk as part of a tuple insert or + * update that would have its own XLOG record that must follow the NEXTOID + * record. Therefore, the standard buffer LSN interlock applied to those + * records will ensure no such OID reaches disk before the NEXTOID record + * does. + * + * Note, however, that the above statement only covers state "within" the + * database. When we use a generated OID as a file or directory name, we + * are in a sense violating the basic WAL rule, because that filesystem + * change may reach disk before the NEXTOID WAL record does. The impact + * of this is that if a database crash occurs immediately afterward, we + * might after restart re-generate the same OID and find that it conflicts + * with the leftover file or directory. But since for safety's sake we + * always loop until finding a nonconflicting filename, this poses no real + * problem in practice. See pgsql-hackers discussion 27-Sep-2006. + */ + } + + /* + * Write an XLOG SWITCH record. + * + * Here we just blindly issue an XLogInsert request for the record. + * All the magic happens inside XLogInsert. + * + * The return value is either the end+1 address of the switch record, + * or the end+1 address of the prior segment if we did not need to + * write a switch record because we are already at segment start. + */ + XLogRecPtr + RequestXLogSwitch(void) + { + XLogRecPtr RecPtr; + XLogRecData rdata; + + /* XLOG SWITCH, alone among xlog record types, has no data */ + rdata.buffer = InvalidBuffer; + rdata.data = NULL; + rdata.len = 0; + rdata.next = NULL; + + RecPtr = XLogInsert(RM_XLOG_ID, XLOG_SWITCH, &rdata); + + return RecPtr; + } + + /* + * XLOG resource manager's routines + */ + void + xlog_redo(XLogRecPtr lsn, XLogRecord *record) + { + uint8 info = record->xl_info & ~XLR_INFO_MASK; + + /* Backup blocks are not used in xlog records */ + Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK)); + + if (info == XLOG_NEXTOID) + { + Oid nextOid; + + memcpy(&nextOid, XLogRecGetData(record), sizeof(Oid)); + if (ShmemVariableCache->nextOid < nextOid) + { + ShmemVariableCache->nextOid = nextOid; + ShmemVariableCache->oidCount = 0; + } + } + else if (info == XLOG_CHECKPOINT_SHUTDOWN) + { + CheckPoint checkPoint; + + memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint)); + /* In a SHUTDOWN checkpoint, believe the counters exactly */ + ShmemVariableCache->nextXid = checkPoint.nextXid; + ShmemVariableCache->nextOid = checkPoint.nextOid; + ShmemVariableCache->oidCount = 0; + MultiXactSetNextMXact(checkPoint.nextMulti, + checkPoint.nextMultiOffset); + + /* ControlFile->checkPointCopy always tracks the latest ckpt XID */ + ControlFile->checkPointCopy.nextXidEpoch = checkPoint.nextXidEpoch; + ControlFile->checkPointCopy.nextXid = checkPoint.nextXid; + + /* + * TLI may change in a shutdown checkpoint, but it shouldn't decrease + */ + if (checkPoint.ThisTimeLineID != ThisTimeLineID) + { + if (checkPoint.ThisTimeLineID < ThisTimeLineID || + !list_member_int(expectedTLIs, + (int) checkPoint.ThisTimeLineID)) + ereport(PANIC, + (errmsg("unexpected timeline ID %u (after %u) in checkpoint record", + checkPoint.ThisTimeLineID, ThisTimeLineID))); + /* Following WAL records should be run with new TLI */ + ThisTimeLineID = checkPoint.ThisTimeLineID; + } + + RecoveryRestartPoint(&checkPoint); + } + else if (info == XLOG_CHECKPOINT_ONLINE) + { + CheckPoint checkPoint; + + memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint)); + /* In an ONLINE checkpoint, treat the counters like NEXTOID */ + if (TransactionIdPrecedes(ShmemVariableCache->nextXid, + checkPoint.nextXid)) + ShmemVariableCache->nextXid = checkPoint.nextXid; + if (ShmemVariableCache->nextOid < checkPoint.nextOid) + { + ShmemVariableCache->nextOid = checkPoint.nextOid; + ShmemVariableCache->oidCount = 0; + } + MultiXactAdvanceNextMXact(checkPoint.nextMulti, + checkPoint.nextMultiOffset); + + /* ControlFile->checkPointCopy always tracks the latest ckpt XID */ + ControlFile->checkPointCopy.nextXidEpoch = checkPoint.nextXidEpoch; + ControlFile->checkPointCopy.nextXid = checkPoint.nextXid; + + /* TLI should not change in an on-line checkpoint */ + if (checkPoint.ThisTimeLineID != ThisTimeLineID) + ereport(PANIC, + (errmsg("unexpected timeline ID %u (should be %u) in checkpoint record", + checkPoint.ThisTimeLineID, ThisTimeLineID))); + + RecoveryRestartPoint(&checkPoint); + } + else if (info == XLOG_NOOP) + { + /* nothing to do here */ + } + else if (info == XLOG_SWITCH) + { + /* nothing to do here */ + } + } + + void + xlog_desc(StringInfo buf, uint8 xl_info, char *rec) + { + uint8 info = xl_info & ~XLR_INFO_MASK; + + if (info == XLOG_CHECKPOINT_SHUTDOWN || + info == XLOG_CHECKPOINT_ONLINE) + { + CheckPoint *checkpoint = (CheckPoint *) rec; + + appendStringInfo(buf, "checkpoint: redo %X/%X; " + "tli %u; xid %u/%u; oid %u; multi %u; offset %u; %s", + checkpoint->redo.xlogid, checkpoint->redo.xrecoff, + checkpoint->ThisTimeLineID, + checkpoint->nextXidEpoch, checkpoint->nextXid, + checkpoint->nextOid, + checkpoint->nextMulti, + checkpoint->nextMultiOffset, + (info == XLOG_CHECKPOINT_SHUTDOWN) ? "shutdown" : "online"); + } + else if (info == XLOG_NOOP) + { + appendStringInfo(buf, "xlog no-op"); + } + else if (info == XLOG_NEXTOID) + { + Oid nextOid; + + memcpy(&nextOid, rec, sizeof(Oid)); + appendStringInfo(buf, "nextOid: %u", nextOid); + } + else if (info == XLOG_SWITCH) + { + appendStringInfo(buf, "xlog switch"); + } + else + appendStringInfo(buf, "UNKNOWN"); + } + + #ifdef WAL_DEBUG + + static void + xlog_outrec(StringInfo buf, XLogRecord *record) + { + int i; + + appendStringInfo(buf, "prev %X/%X; xid %u", + record->xl_prev.xlogid, record->xl_prev.xrecoff, + record->xl_xid); + + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + if (record->xl_info & XLR_SET_BKP_BLOCK(i)) + appendStringInfo(buf, "; bkpb%d", i + 1); + } + + appendStringInfo(buf, ": %s", RmgrTable[record->xl_rmid].rm_name); + } + #endif /* WAL_DEBUG */ + + + /* + * Return the (possible) sync flag used for opening a file, depending on the + * value of the GUC wal_sync_method. + */ + static int + get_sync_bit(int method) + { + /* If fsync is disabled, never open in sync mode */ + if (!enableFsync) + return 0; + + switch (method) + { + /* + * enum values for all sync options are defined even if they are not + * supported on the current platform. But if not, they are not + * included in the enum option array, and therefore will never be seen + * here. + */ + case SYNC_METHOD_FSYNC: + case SYNC_METHOD_FSYNC_WRITETHROUGH: + case SYNC_METHOD_FDATASYNC: + return 0; + #ifdef OPEN_SYNC_FLAG + case SYNC_METHOD_OPEN: + return OPEN_SYNC_FLAG; + #endif + #ifdef OPEN_DATASYNC_FLAG + case SYNC_METHOD_OPEN_DSYNC: + return OPEN_DATASYNC_FLAG; + #endif + default: + /* can't happen (unless we are out of sync with option array) */ + elog(ERROR, "unrecognized wal_sync_method: %d", method); + return 0; /* silence warning */ + } + } + + /* + * GUC support + */ + bool + assign_xlog_sync_method(int new_sync_method, bool doit, GucSource source) + { + if (!doit) + return true; + + if (sync_method != new_sync_method) + { + /* + * To ensure that no blocks escape unsynced, force an fsync on the + * currently open log segment (if any). Also, if the open flag is + * changing, close the log file so it will be reopened (with new flag + * bit) at next use. + */ + if (openLogFile >= 0) + { + if (pg_fsync(openLogFile) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync log file %u, segment %u: %m", + openLogId, openLogSeg))); + if (get_sync_bit(sync_method) != get_sync_bit(new_sync_method)) + XLogFileClose(); + } + } + + return true; + } + + + /* + * Issue appropriate kind of fsync (if any) on the current XLOG output file + */ + static void + issue_xlog_fsync(void) + { + switch (sync_method) + { + case SYNC_METHOD_FSYNC: + if (pg_fsync_no_writethrough(openLogFile) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync log file %u, segment %u: %m", + openLogId, openLogSeg))); + break; + #ifdef HAVE_FSYNC_WRITETHROUGH + case SYNC_METHOD_FSYNC_WRITETHROUGH: + if (pg_fsync_writethrough(openLogFile) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync write-through log file %u, segment %u: %m", + openLogId, openLogSeg))); + break; + #endif + #ifdef HAVE_FDATASYNC + case SYNC_METHOD_FDATASYNC: + if (pg_fdatasync(openLogFile) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fdatasync log file %u, segment %u: %m", + openLogId, openLogSeg))); + break; + #endif + case SYNC_METHOD_OPEN: + case SYNC_METHOD_OPEN_DSYNC: + /* write synced it already */ + break; + default: + elog(PANIC, "unrecognized wal_sync_method: %d", sync_method); + break; + } + } + + + /* + * pg_start_backup: set up for taking an on-line backup dump + * + * Essentially what this does is to create a backup label file in $PGDATA, + * where it will be archived as part of the backup dump. The label file + * contains the user-supplied label string (typically this would be used + * to tell where the backup dump will be stored) and the starting time and + * starting WAL location for the dump. + */ + Datum + pg_start_backup(PG_FUNCTION_ARGS) + { + text *backupid = PG_GETARG_TEXT_P(0); + char *backupidstr; + XLogRecPtr checkpointloc; + XLogRecPtr startpoint; + pg_time_t stamp_time; + char strfbuf[128]; + char xlogfilename[MAXFNAMELEN]; + uint32 _logId; + uint32 _logSeg; + struct stat stat_buf; + FILE *fp; + + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("must be superuser to run a backup"))); + + if (!XLogArchivingActive()) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("WAL archiving is not active"), + errhint("archive_mode must be enabled at server start."))); + + if (!XLogArchiveCommandSet()) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("WAL archiving is not active"), + errhint("archive_command must be defined before " + "online backups can be made safely."))); + + backupidstr = text_to_cstring(backupid); + + /* + * Mark backup active in shared memory. We must do full-page WAL writes + * during an on-line backup even if not doing so at other times, because + * it's quite possible for the backup dump to obtain a "torn" (partially + * written) copy of a database page if it reads the page concurrently with + * our write to the same page. This can be fixed as long as the first + * write to the page in the WAL sequence is a full-page write. Hence, we + * turn on forcePageWrites and then force a CHECKPOINT, to ensure there + * are no dirty pages in shared memory that might get dumped while the + * backup is in progress without having a corresponding WAL record. (Once + * the backup is complete, we need not force full-page writes anymore, + * since we expect that any pages not modified during the backup interval + * must have been correctly captured by the backup.) + * + * We must hold WALInsertLock to change the value of forcePageWrites, to + * ensure adequate interlocking against XLogInsert(). + */ + LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); + if (XLogCtl->Insert.forcePageWrites) + { + LWLockRelease(WALInsertLock); + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("a backup is already in progress"), + errhint("Run pg_stop_backup() and try again."))); + } + XLogCtl->Insert.forcePageWrites = true; + LWLockRelease(WALInsertLock); + + /* Ensure we release forcePageWrites if fail below */ + PG_ENSURE_ERROR_CLEANUP(pg_start_backup_callback, (Datum) 0); + { + /* + * Force a CHECKPOINT. Aside from being necessary to prevent torn + * page problems, this guarantees that two successive backup runs will + * have different checkpoint positions and hence different history + * file names, even if nothing happened in between. + * + * We don't use CHECKPOINT_IMMEDIATE, hence this can take awhile. + */ + RequestCheckpoint(CHECKPOINT_FORCE | CHECKPOINT_WAIT); + + /* + * Now we need to fetch the checkpoint record location, and also its + * REDO pointer. The oldest point in WAL that would be needed to + * restore starting from the checkpoint is precisely the REDO pointer. + */ + LWLockAcquire(ControlFileLock, LW_EXCLUSIVE); + checkpointloc = ControlFile->checkPoint; + startpoint = ControlFile->checkPointCopy.redo; + LWLockRelease(ControlFileLock); + + XLByteToSeg(startpoint, _logId, _logSeg); + XLogFileName(xlogfilename, ThisTimeLineID, _logId, _logSeg); + + /* Use the log timezone here, not the session timezone */ + stamp_time = (pg_time_t) time(NULL); + pg_strftime(strfbuf, sizeof(strfbuf), + "%Y-%m-%d %H:%M:%S %Z", + pg_localtime(&stamp_time, log_timezone)); + + /* + * Check for existing backup label --- implies a backup is already + * running. (XXX given that we checked forcePageWrites above, maybe + * it would be OK to just unlink any such label file?) + */ + if (stat(BACKUP_LABEL_FILE, &stat_buf) != 0) + { + if (errno != ENOENT) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not stat file \"%s\": %m", + BACKUP_LABEL_FILE))); + } + else + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("a backup is already in progress"), + errhint("If you're sure there is no backup in progress, remove file \"%s\" and try again.", + BACKUP_LABEL_FILE))); + + /* + * Okay, write the file + */ + fp = AllocateFile(BACKUP_LABEL_FILE, "w"); + if (!fp) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not create file \"%s\": %m", + BACKUP_LABEL_FILE))); + fprintf(fp, "START WAL LOCATION: %X/%X (file %s)\n", + startpoint.xlogid, startpoint.xrecoff, xlogfilename); + fprintf(fp, "CHECKPOINT LOCATION: %X/%X\n", + checkpointloc.xlogid, checkpointloc.xrecoff); + fprintf(fp, "START TIME: %s\n", strfbuf); + fprintf(fp, "LABEL: %s\n", backupidstr); + if (fflush(fp) || ferror(fp) || FreeFile(fp)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write file \"%s\": %m", + BACKUP_LABEL_FILE))); + } + PG_END_ENSURE_ERROR_CLEANUP(pg_start_backup_callback, (Datum) 0); + + /* + * We're done. As a convenience, return the starting WAL location. + */ + snprintf(xlogfilename, sizeof(xlogfilename), "%X/%X", + startpoint.xlogid, startpoint.xrecoff); + PG_RETURN_TEXT_P(cstring_to_text(xlogfilename)); + } + + /* Error cleanup callback for pg_start_backup */ + static void + pg_start_backup_callback(int code, Datum arg) + { + /* Turn off forcePageWrites on failure */ + LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); + XLogCtl->Insert.forcePageWrites = false; + LWLockRelease(WALInsertLock); + } + + /* + * pg_stop_backup: finish taking an on-line backup dump + * + * We remove the backup label file created by pg_start_backup, and instead + * create a backup history file in pg_xlog (whence it will immediately be + * archived). The backup history file contains the same info found in + * the label file, plus the backup-end time and WAL location. + * Note: different from CancelBackup which just cancels online backup mode. + */ + Datum + pg_stop_backup(PG_FUNCTION_ARGS) + { + XLogRecPtr startpoint; + XLogRecPtr stoppoint; + pg_time_t stamp_time; + char strfbuf[128]; + char histfilepath[MAXPGPATH]; + char startxlogfilename[MAXFNAMELEN]; + char stopxlogfilename[MAXFNAMELEN]; + char lastxlogfilename[MAXFNAMELEN]; + char histfilename[MAXFNAMELEN]; + uint32 _logId; + uint32 _logSeg; + FILE *lfp; + FILE *fp; + char ch; + int ich; + int seconds_before_warning; + int waits = 0; + + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + (errmsg("must be superuser to run a backup")))); + + if (!XLogArchivingActive()) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("WAL archiving is not active"), + errhint("archive_mode must be enabled at server start."))); + + /* + * OK to clear forcePageWrites + */ + LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); + XLogCtl->Insert.forcePageWrites = false; + LWLockRelease(WALInsertLock); + + /* + * Force a switch to a new xlog segment file, so that the backup is valid + * as soon as archiver moves out the current segment file. We'll report + * the end address of the XLOG SWITCH record as the backup stopping point. + */ + stoppoint = RequestXLogSwitch(); + + XLByteToSeg(stoppoint, _logId, _logSeg); + XLogFileName(stopxlogfilename, ThisTimeLineID, _logId, _logSeg); + + /* Use the log timezone here, not the session timezone */ + stamp_time = (pg_time_t) time(NULL); + pg_strftime(strfbuf, sizeof(strfbuf), + "%Y-%m-%d %H:%M:%S %Z", + pg_localtime(&stamp_time, log_timezone)); + + /* + * Open the existing label file + */ + lfp = AllocateFile(BACKUP_LABEL_FILE, "r"); + if (!lfp) + { + if (errno != ENOENT) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", + BACKUP_LABEL_FILE))); + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("a backup is not in progress"))); + } + + /* + * Read and parse the START WAL LOCATION line (this code is pretty crude, + * but we are not expecting any variability in the file format). + */ + if (fscanf(lfp, "START WAL LOCATION: %X/%X (file %24s)%c", + &startpoint.xlogid, &startpoint.xrecoff, startxlogfilename, + &ch) != 4 || ch != '\n') + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE))); + + /* + * Write the backup history file + */ + XLByteToSeg(startpoint, _logId, _logSeg); + BackupHistoryFilePath(histfilepath, ThisTimeLineID, _logId, _logSeg, + startpoint.xrecoff % XLogSegSize); + fp = AllocateFile(histfilepath, "w"); + if (!fp) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not create file \"%s\": %m", + histfilepath))); + fprintf(fp, "START WAL LOCATION: %X/%X (file %s)\n", + startpoint.xlogid, startpoint.xrecoff, startxlogfilename); + fprintf(fp, "STOP WAL LOCATION: %X/%X (file %s)\n", + stoppoint.xlogid, stoppoint.xrecoff, stopxlogfilename); + /* transfer remaining lines from label to history file */ + while ((ich = fgetc(lfp)) != EOF) + fputc(ich, fp); + fprintf(fp, "STOP TIME: %s\n", strfbuf); + if (fflush(fp) || ferror(fp) || FreeFile(fp)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write file \"%s\": %m", + histfilepath))); + + /* + * Close and remove the backup label file + */ + if (ferror(lfp) || FreeFile(lfp)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", + BACKUP_LABEL_FILE))); + if (unlink(BACKUP_LABEL_FILE) != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not remove file \"%s\": %m", + BACKUP_LABEL_FILE))); + + /* + * Clean out any no-longer-needed history files. As a side effect, this + * will post a .ready file for the newly created history file, notifying + * the archiver that history file may be archived immediately. + */ + CleanupBackupHistory(); + + /* + * Wait until both the last WAL file filled during backup and the history + * file have been archived. We assume that the alphabetic sorting + * property of the WAL files ensures any earlier WAL files are safely + * archived as well. + * + * We wait forever, since archive_command is supposed to work and + * we assume the admin wanted his backup to work completely. If you + * don't wish to wait, you can set statement_timeout. + */ + XLByteToPrevSeg(stoppoint, _logId, _logSeg); + XLogFileName(lastxlogfilename, ThisTimeLineID, _logId, _logSeg); + + XLByteToSeg(startpoint, _logId, _logSeg); + BackupHistoryFileName(histfilename, ThisTimeLineID, _logId, _logSeg, + startpoint.xrecoff % XLogSegSize); + + seconds_before_warning = 60; + waits = 0; + + while (XLogArchiveIsBusy(lastxlogfilename) || + XLogArchiveIsBusy(histfilename)) + { + CHECK_FOR_INTERRUPTS(); + + pg_usleep(1000000L); + + if (++waits >= seconds_before_warning) + { + seconds_before_warning *= 2; /* This wraps in >10 years... */ + ereport(WARNING, + (errmsg("pg_stop_backup still waiting for archive to complete (%d seconds elapsed)", + waits))); + } + } + + /* + * We're done. As a convenience, return the ending WAL location. + */ + snprintf(stopxlogfilename, sizeof(stopxlogfilename), "%X/%X", + stoppoint.xlogid, stoppoint.xrecoff); + PG_RETURN_TEXT_P(cstring_to_text(stopxlogfilename)); + } + + /* + * pg_switch_xlog: switch to next xlog file + */ + Datum + pg_switch_xlog(PG_FUNCTION_ARGS) + { + XLogRecPtr switchpoint; + char location[MAXFNAMELEN]; + + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + (errmsg("must be superuser to switch transaction log files")))); + + switchpoint = RequestXLogSwitch(); + + /* + * As a convenience, return the WAL location of the switch record + */ + snprintf(location, sizeof(location), "%X/%X", + switchpoint.xlogid, switchpoint.xrecoff); + PG_RETURN_TEXT_P(cstring_to_text(location)); + } + + /* + * Report the current WAL write location (same format as pg_start_backup etc) + * + * This is useful for determining how much of WAL is visible to an external + * archiving process. Note that the data before this point is written out + * to the kernel, but is not necessarily synced to disk. + */ + Datum + pg_current_xlog_location(PG_FUNCTION_ARGS) + { + char location[MAXFNAMELEN]; + + /* Make sure we have an up-to-date local LogwrtResult */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease(&xlogctl->info_lck); + } + + snprintf(location, sizeof(location), "%X/%X", + LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff); + PG_RETURN_TEXT_P(cstring_to_text(location)); + } + + /* + * Report the current WAL insert location (same format as pg_start_backup etc) + * + * This function is mostly for debugging purposes. + */ + Datum + pg_current_xlog_insert_location(PG_FUNCTION_ARGS) + { + XLogCtlInsert *Insert = &XLogCtl->Insert; + XLogRecPtr current_recptr; + char location[MAXFNAMELEN]; + + /* + * Get the current end-of-WAL position ... shared lock is sufficient + */ + LWLockAcquire(WALInsertLock, LW_SHARED); + INSERT_RECPTR(current_recptr, Insert, Insert->curridx); + LWLockRelease(WALInsertLock); + + snprintf(location, sizeof(location), "%X/%X", + current_recptr.xlogid, current_recptr.xrecoff); + PG_RETURN_TEXT_P(cstring_to_text(location)); + } + + /* + * Compute an xlog file name and decimal byte offset given a WAL location, + * such as is returned by pg_stop_backup() or pg_xlog_switch(). + * + * Note that a location exactly at a segment boundary is taken to be in + * the previous segment. This is usually the right thing, since the + * expected usage is to determine which xlog file(s) are ready to archive. + */ + Datum + pg_xlogfile_name_offset(PG_FUNCTION_ARGS) + { + text *location = PG_GETARG_TEXT_P(0); + char *locationstr; + unsigned int uxlogid; + unsigned int uxrecoff; + uint32 xlogid; + uint32 xlogseg; + uint32 xrecoff; + XLogRecPtr locationpoint; + char xlogfilename[MAXFNAMELEN]; + Datum values[2]; + bool isnull[2]; + TupleDesc resultTupleDesc; + HeapTuple resultHeapTuple; + Datum result; + + /* + * Read input and parse + */ + locationstr = text_to_cstring(location); + + if (sscanf(locationstr, "%X/%X", &uxlogid, &uxrecoff) != 2) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("could not parse transaction log location \"%s\"", + locationstr))); + + locationpoint.xlogid = uxlogid; + locationpoint.xrecoff = uxrecoff; + + /* + * Construct a tuple descriptor for the result row. This must match this + * function's pg_proc entry! + */ + resultTupleDesc = CreateTemplateTupleDesc(2, false); + TupleDescInitEntry(resultTupleDesc, (AttrNumber) 1, "file_name", + TEXTOID, -1, 0); + TupleDescInitEntry(resultTupleDesc, (AttrNumber) 2, "file_offset", + INT4OID, -1, 0); + + resultTupleDesc = BlessTupleDesc(resultTupleDesc); + + /* + * xlogfilename + */ + XLByteToPrevSeg(locationpoint, xlogid, xlogseg); + XLogFileName(xlogfilename, ThisTimeLineID, xlogid, xlogseg); + + values[0] = CStringGetTextDatum(xlogfilename); + isnull[0] = false; + + /* + * offset + */ + xrecoff = locationpoint.xrecoff - xlogseg * XLogSegSize; + + values[1] = UInt32GetDatum(xrecoff); + isnull[1] = false; + + /* + * Tuple jam: Having first prepared your Datums, then squash together + */ + resultHeapTuple = heap_form_tuple(resultTupleDesc, values, isnull); + + result = HeapTupleGetDatum(resultHeapTuple); + + PG_RETURN_DATUM(result); + } + + /* + * Compute an xlog file name given a WAL location, + * such as is returned by pg_stop_backup() or pg_xlog_switch(). + */ + Datum + pg_xlogfile_name(PG_FUNCTION_ARGS) + { + text *location = PG_GETARG_TEXT_P(0); + char *locationstr; + unsigned int uxlogid; + unsigned int uxrecoff; + uint32 xlogid; + uint32 xlogseg; + XLogRecPtr locationpoint; + char xlogfilename[MAXFNAMELEN]; + + locationstr = text_to_cstring(location); + + if (sscanf(locationstr, "%X/%X", &uxlogid, &uxrecoff) != 2) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("could not parse transaction log location \"%s\"", + locationstr))); + + locationpoint.xlogid = uxlogid; + locationpoint.xrecoff = uxrecoff; + + XLByteToPrevSeg(locationpoint, xlogid, xlogseg); + XLogFileName(xlogfilename, ThisTimeLineID, xlogid, xlogseg); + + PG_RETURN_TEXT_P(cstring_to_text(xlogfilename)); + } + + /* + * read_backup_label: check to see if a backup_label file is present + * + * If we see a backup_label during recovery, we assume that we are recovering + * from a backup dump file, and we therefore roll forward from the checkpoint + * identified by the label file, NOT what pg_control says. This avoids the + * problem that pg_control might have been archived one or more checkpoints + * later than the start of the dump, and so if we rely on it as the start + * point, we will fail to restore a consistent database state. + * + * We also attempt to retrieve the corresponding backup history file. + * If successful, set *minRecoveryLoc to constrain valid PITR stopping + * points. + * + * Returns TRUE if a backup_label was found (and fills the checkpoint + * location into *checkPointLoc); returns FALSE if not. + */ + static bool + read_backup_label(XLogRecPtr *checkPointLoc, XLogRecPtr *minRecoveryLoc) + { + XLogRecPtr startpoint; + XLogRecPtr stoppoint; + char histfilename[MAXFNAMELEN]; + char histfilepath[MAXPGPATH]; + char startxlogfilename[MAXFNAMELEN]; + char stopxlogfilename[MAXFNAMELEN]; + TimeLineID tli; + uint32 _logId; + uint32 _logSeg; + FILE *lfp; + FILE *fp; + char ch; + + /* Default is to not constrain recovery stop point */ + minRecoveryLoc->xlogid = 0; + minRecoveryLoc->xrecoff = 0; + + /* + * See if label file is present + */ + lfp = AllocateFile(BACKUP_LABEL_FILE, "r"); + if (!lfp) + { + if (errno != ENOENT) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", + BACKUP_LABEL_FILE))); + return false; /* it's not there, all is fine */ + } + + /* + * Read and parse the START WAL LOCATION and CHECKPOINT lines (this code + * is pretty crude, but we are not expecting any variability in the file + * format). + */ + if (fscanf(lfp, "START WAL LOCATION: %X/%X (file %08X%16s)%c", + &startpoint.xlogid, &startpoint.xrecoff, &tli, + startxlogfilename, &ch) != 5 || ch != '\n') + ereport(FATAL, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE))); + if (fscanf(lfp, "CHECKPOINT LOCATION: %X/%X%c", + &checkPointLoc->xlogid, &checkPointLoc->xrecoff, + &ch) != 3 || ch != '\n') + ereport(FATAL, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE))); + if (ferror(lfp) || FreeFile(lfp)) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", + BACKUP_LABEL_FILE))); + + /* + * Try to retrieve the backup history file (no error if we can't) + */ + XLByteToSeg(startpoint, _logId, _logSeg); + BackupHistoryFileName(histfilename, tli, _logId, _logSeg, + startpoint.xrecoff % XLogSegSize); + + if (InArchiveRecovery) + RestoreArchivedFile(histfilepath, histfilename, "RECOVERYHISTORY", 0); + else + BackupHistoryFilePath(histfilepath, tli, _logId, _logSeg, + startpoint.xrecoff % XLogSegSize); + + fp = AllocateFile(histfilepath, "r"); + if (fp) + { + /* + * Parse history file to identify stop point. + */ + if (fscanf(fp, "START WAL LOCATION: %X/%X (file %24s)%c", + &startpoint.xlogid, &startpoint.xrecoff, startxlogfilename, + &ch) != 4 || ch != '\n') + ereport(FATAL, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("invalid data in file \"%s\"", histfilename))); + if (fscanf(fp, "STOP WAL LOCATION: %X/%X (file %24s)%c", + &stoppoint.xlogid, &stoppoint.xrecoff, stopxlogfilename, + &ch) != 4 || ch != '\n') + ereport(FATAL, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("invalid data in file \"%s\"", histfilename))); + *minRecoveryLoc = stoppoint; + if (ferror(fp) || FreeFile(fp)) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", + histfilepath))); + } + + return true; + } + + /* + * Error context callback for errors occurring during rm_redo(). + */ + static void + rm_redo_error_callback(void *arg) + { + XLogRecord *record = (XLogRecord *) arg; + StringInfoData buf; + + initStringInfo(&buf); + RmgrTable[record->xl_rmid].rm_desc(&buf, + record->xl_info, + XLogRecGetData(record)); + + /* don't bother emitting empty description */ + if (buf.len > 0) + errcontext("xlog redo %s", buf.data); + + pfree(buf.data); + } + + /* + * BackupInProgress: check if online backup mode is active + * + * This is done by checking for existence of the "backup_label" file. + */ + bool + BackupInProgress(void) + { + struct stat stat_buf; + + return (stat(BACKUP_LABEL_FILE, &stat_buf) == 0); + } + + /* + * CancelBackup: rename the "backup_label" file to cancel backup mode + * + * If the "backup_label" file exists, it will be renamed to "backup_label.old". + * Note that this will render an online backup in progress useless. + * To correctly finish an online backup, pg_stop_backup must be called. + */ + void + CancelBackup(void) + { + struct stat stat_buf; + + /* if the file is not there, return */ + if (stat(BACKUP_LABEL_FILE, &stat_buf) < 0) + return; + + /* remove leftover file from previously cancelled backup if it exists */ + unlink(BACKUP_LABEL_OLD); + + if (rename(BACKUP_LABEL_FILE, BACKUP_LABEL_OLD) == 0) + { + ereport(LOG, + (errmsg("online backup mode cancelled"), + errdetail("\"%s\" was renamed to \"%s\".", + BACKUP_LABEL_FILE, BACKUP_LABEL_OLD))); + } + else + { + ereport(WARNING, + (errcode_for_file_access(), + errmsg("online backup mode was not cancelled"), + errdetail("Could not rename \"%s\" to \"%s\": %m.", + BACKUP_LABEL_FILE, BACKUP_LABEL_OLD))); + } + } + diff -rcN Postgresql-CVS-20090313.org/src/backend/access/transam/xlog.c.rej Postgresql-CVS-20090313/src/backend/access/transam/xlog.c.rej *** Postgresql-CVS-20090313.org/src/backend/access/transam/xlog.c.rej 1970-01-01 09:00:00.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/transam/xlog.c.rej 2009-03-13 16:37:09.000000000 +0900 *************** *** 0 **** --- 1,45 ---- + *************** + *** 5170,5176 **** + bool recoveryContinue = true; + bool recoveryApply = true; + bool reachedMinRecoveryPoint = false; + - ErrorContextCallback errcontext; + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + --- 5212,5217 ---- + bool recoveryContinue = true; + bool recoveryApply = true; + bool reachedMinRecoveryPoint = false; + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + *************** + *** 5273,5292 **** + break; + } + + - /* Setup error traceback support for ereport() */ + - errcontext.callback = rm_redo_error_callback; + - errcontext.arg = (void *) record; + - errcontext.previous = error_context_stack; + - error_context_stack = &errcontext; + - + - /* nextXid must be beyond record's xid */ + - if (TransactionIdFollowsOrEquals(record->xl_xid, + - ShmemVariableCache->nextXid)) + - { + - ShmemVariableCache->nextXid = record->xl_xid; + - TransactionIdAdvance(ShmemVariableCache->nextXid); + - } + - + /* + * Update shared replayEndRecPtr before replaying this + * record, so that XLogFlush will update minRecoveryPoint + --- 5314,5319 ---- + break; + } + + /* + * Update shared replayEndRecPtr before replaying this + * record, so that XLogFlush will update minRecoveryPoint diff -rcN Postgresql-CVS-20090313.org/src/backend/access/transam/xlog.c~ Postgresql-CVS-20090313/src/backend/access/transam/xlog.c~ *** Postgresql-CVS-20090313.org/src/backend/access/transam/xlog.c~ 1970-01-01 09:00:00.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/access/transam/xlog.c~ 2009-03-13 16:37:09.000000000 +0900 *************** *** 0 **** --- 1,7385 ---- + /*------------------------------------------------------------------------- + * + * xlog.c + * PostgreSQL transaction log manager + * + * + * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.329 2009/01/23 11:19:34 heikki Exp $ + * + *------------------------------------------------------------------------- + */ + + #include "postgres.h" + + #include + #include + #include + #include + #include + #include + #include + #include + + #include "access/clog.h" + #include "access/multixact.h" + #include "access/subtrans.h" + #include "access/transam.h" + #include "access/tuptoaster.h" + #include "access/twophase.h" + #include "access/xact.h" + #include "access/xlog_internal.h" + #include "access/xlogutils.h" + #include "catalog/catversion.h" + #include "catalog/pg_control.h" + #include "catalog/pg_type.h" + #include "funcapi.h" + #include "miscadmin.h" + #include "pgstat.h" + #include "postmaster/bgwriter.h" + #include "storage/bufmgr.h" + #include "storage/fd.h" + #include "storage/ipc.h" + #include "storage/pmsignal.h" + #include "storage/procarray.h" + #include "storage/smgr.h" + #include "storage/spin.h" + #include "utils/builtins.h" + #include "utils/guc.h" + #include "utils/ps_status.h" + #include "pg_trace.h" + + + /* File path names (all relative to $PGDATA) */ + #define BACKUP_LABEL_FILE "backup_label" + #define BACKUP_LABEL_OLD "backup_label.old" + #define RECOVERY_COMMAND_FILE "recovery.conf" + #define RECOVERY_COMMAND_DONE "recovery.done" + + + /* User-settable parameters */ + int CheckPointSegments = 3; + int XLOGbuffers = 8; + int XLogArchiveTimeout = 0; + bool XLogArchiveMode = false; + char *XLogArchiveCommand = NULL; + bool fullPageWrites = true; + bool log_checkpoints = false; + int sync_method = DEFAULT_SYNC_METHOD; + + #ifdef WAL_DEBUG + bool XLOG_DEBUG = false; + #endif + + /* + * XLOGfileslop is the maximum number of preallocated future XLOG segments. + * When we are done with an old XLOG segment file, we will recycle it as a + * future XLOG segment as long as there aren't already XLOGfileslop future + * segments; else we'll delete it. This could be made a separate GUC + * variable, but at present I think it's sufficient to hardwire it as + * 2*CheckPointSegments+1. Under normal conditions, a checkpoint will free + * no more than 2*CheckPointSegments log segments, and we want to recycle all + * of them; the +1 allows boundary cases to happen without wasting a + * delete/create-segment cycle. + */ + #define XLOGfileslop (2*CheckPointSegments + 1) + + /* + * GUC support + */ + const struct config_enum_entry sync_method_options[] = { + {"fsync", SYNC_METHOD_FSYNC, false}, + #ifdef HAVE_FSYNC_WRITETHROUGH + {"fsync_writethrough", SYNC_METHOD_FSYNC_WRITETHROUGH, false}, + #endif + #ifdef HAVE_FDATASYNC + {"fdatasync", SYNC_METHOD_FDATASYNC, false}, + #endif + #ifdef OPEN_SYNC_FLAG + {"open_sync", SYNC_METHOD_OPEN, false}, + #endif + #ifdef OPEN_DATASYNC_FLAG + {"open_datasync", SYNC_METHOD_OPEN_DSYNC, false}, + #endif + {NULL, 0, false} + }; + + /* + * Statistics for current checkpoint are collected in this global struct. + * Because only the background writer or a stand-alone backend can perform + * checkpoints, this will be unused in normal backends. + */ + CheckpointStatsData CheckpointStats; + + /* + * ThisTimeLineID will be same in all backends --- it identifies current + * WAL timeline for the database system. + */ + TimeLineID ThisTimeLineID = 0; + + /* Are we doing recovery from XLOG? */ + bool InRecovery = false; + + /* Are we recovering using offline XLOG archives? */ + static bool InArchiveRecovery = false; + + /* Was the last xlog file restored from archive, or local? */ + static bool restoredFromArchive = false; + + /* options taken from recovery.conf */ + static char *recoveryRestoreCommand = NULL; + static bool recoveryTarget = false; + static bool recoveryTargetExact = false; + static bool recoveryTargetInclusive = true; + static bool recoveryLogRestartpoints = false; + static TransactionId recoveryTargetXid; + static TimestampTz recoveryTargetTime; + static TimestampTz recoveryLastXTime = 0; + + /* if recoveryStopsHere returns true, it saves actual stop xid/time here */ + static TransactionId recoveryStopXid; + static TimestampTz recoveryStopTime; + static bool recoveryStopAfter; + + /* + * During normal operation, the only timeline we care about is ThisTimeLineID. + * During recovery, however, things are more complicated. To simplify life + * for rmgr code, we keep ThisTimeLineID set to the "current" timeline as we + * scan through the WAL history (that is, it is the line that was active when + * the currently-scanned WAL record was generated). We also need these + * timeline values: + * + * recoveryTargetTLI: the desired timeline that we want to end in. + * + * expectedTLIs: an integer list of recoveryTargetTLI and the TLIs of + * its known parents, newest first (so recoveryTargetTLI is always the + * first list member). Only these TLIs are expected to be seen in the WAL + * segments we read, and indeed only these TLIs will be considered as + * candidate WAL files to open at all. + * + * curFileTLI: the TLI appearing in the name of the current input WAL file. + * (This is not necessarily the same as ThisTimeLineID, because we could + * be scanning data that was copied from an ancestor timeline when the current + * file was created.) During a sequential scan we do not allow this value + * to decrease. + */ + static TimeLineID recoveryTargetTLI; + static List *expectedTLIs; + static TimeLineID curFileTLI; + + /* + * ProcLastRecPtr points to the start of the last XLOG record inserted by the + * current backend. It is updated for all inserts. XactLastRecEnd points to + * end+1 of the last record, and is reset when we end a top-level transaction, + * or start a new one; so it can be used to tell if the current transaction has + * created any XLOG records. + */ + static XLogRecPtr ProcLastRecPtr = {0, 0}; + + XLogRecPtr XactLastRecEnd = {0, 0}; + + /* + * RedoRecPtr is this backend's local copy of the REDO record pointer + * (which is almost but not quite the same as a pointer to the most recent + * CHECKPOINT record). We update this from the shared-memory copy, + * XLogCtl->Insert.RedoRecPtr, whenever we can safely do so (ie, when we + * hold the Insert lock). See XLogInsert for details. We are also allowed + * to update from XLogCtl->Insert.RedoRecPtr if we hold the info_lck; + * see GetRedoRecPtr. A freshly spawned backend obtains the value during + * InitXLOGAccess. + */ + static XLogRecPtr RedoRecPtr; + + /*---------- + * Shared-memory data structures for XLOG control + * + * LogwrtRqst indicates a byte position that we need to write and/or fsync + * the log up to (all records before that point must be written or fsynced). + * LogwrtResult indicates the byte positions we have already written/fsynced. + * These structs are identical but are declared separately to indicate their + * slightly different functions. + * + * We do a lot of pushups to minimize the amount of access to lockable + * shared memory values. There are actually three shared-memory copies of + * LogwrtResult, plus one unshared copy in each backend. Here's how it works: + * XLogCtl->LogwrtResult is protected by info_lck + * XLogCtl->Write.LogwrtResult is protected by WALWriteLock + * XLogCtl->Insert.LogwrtResult is protected by WALInsertLock + * One must hold the associated lock to read or write any of these, but + * of course no lock is needed to read/write the unshared LogwrtResult. + * + * XLogCtl->LogwrtResult and XLogCtl->Write.LogwrtResult are both "always + * right", since both are updated by a write or flush operation before + * it releases WALWriteLock. The point of keeping XLogCtl->Write.LogwrtResult + * is that it can be examined/modified by code that already holds WALWriteLock + * without needing to grab info_lck as well. + * + * XLogCtl->Insert.LogwrtResult may lag behind the reality of the other two, + * but is updated when convenient. Again, it exists for the convenience of + * code that is already holding WALInsertLock but not the other locks. + * + * The unshared LogwrtResult may lag behind any or all of these, and again + * is updated when convenient. + * + * The request bookkeeping is simpler: there is a shared XLogCtl->LogwrtRqst + * (protected by info_lck), but we don't need to cache any copies of it. + * + * Note that this all works because the request and result positions can only + * advance forward, never back up, and so we can easily determine which of two + * values is "more up to date". + * + * info_lck is only held long enough to read/update the protected variables, + * so it's a plain spinlock. The other locks are held longer (potentially + * over I/O operations), so we use LWLocks for them. These locks are: + * + * WALInsertLock: must be held to insert a record into the WAL buffers. + * + * WALWriteLock: must be held to write WAL buffers to disk (XLogWrite or + * XLogFlush). + * + * ControlFileLock: must be held to read/update control file or create + * new log file. + * + * CheckpointLock: must be held to do a checkpoint (ensures only one + * checkpointer at a time; currently, with all checkpoints done by the + * bgwriter, this is just pro forma). + * + *---------- + */ + + typedef struct XLogwrtRqst + { + XLogRecPtr Write; /* last byte + 1 to write out */ + XLogRecPtr Flush; /* last byte + 1 to flush */ + } XLogwrtRqst; + + typedef struct XLogwrtResult + { + XLogRecPtr Write; /* last byte + 1 written out */ + XLogRecPtr Flush; /* last byte + 1 flushed */ + } XLogwrtResult; + + /* + * Shared state data for XLogInsert. + */ + typedef struct XLogCtlInsert + { + XLogwrtResult LogwrtResult; /* a recent value of LogwrtResult */ + XLogRecPtr PrevRecord; /* start of previously-inserted record */ + int curridx; /* current block index in cache */ + XLogPageHeader currpage; /* points to header of block in cache */ + char *currpos; /* current insertion point in cache */ + XLogRecPtr RedoRecPtr; /* current redo point for insertions */ + bool forcePageWrites; /* forcing full-page writes for PITR? */ + } XLogCtlInsert; + + /* + * Shared state data for XLogWrite/XLogFlush. + */ + typedef struct XLogCtlWrite + { + XLogwrtResult LogwrtResult; /* current value of LogwrtResult */ + int curridx; /* cache index of next block to write */ + pg_time_t lastSegSwitchTime; /* time of last xlog segment switch */ + } XLogCtlWrite; + + /* + * Total shared-memory state for XLOG. + */ + typedef struct XLogCtlData + { + /* Protected by WALInsertLock: */ + XLogCtlInsert Insert; + + /* Protected by info_lck: */ + XLogwrtRqst LogwrtRqst; + XLogwrtResult LogwrtResult; + uint32 ckptXidEpoch; /* nextXID & epoch of latest checkpoint */ + TransactionId ckptXid; + XLogRecPtr asyncCommitLSN; /* LSN of newest async commit */ + + /* Protected by WALWriteLock: */ + XLogCtlWrite Write; + + /* + * These values do not change after startup, although the pointed-to pages + * and xlblocks values certainly do. Permission to read/write the pages + * and xlblocks values depends on WALInsertLock and WALWriteLock. + */ + char *pages; /* buffers for unwritten XLOG pages */ + XLogRecPtr *xlblocks; /* 1st byte ptr-s + XLOG_BLCKSZ */ + int XLogCacheBlck; /* highest allocated xlog buffer index */ + TimeLineID ThisTimeLineID; + + slock_t info_lck; /* locks shared variables shown above */ + } XLogCtlData; + + static XLogCtlData *XLogCtl = NULL; + + /* + * We maintain an image of pg_control in shared memory. + */ + static ControlFileData *ControlFile = NULL; + + /* + * Macros for managing XLogInsert state. In most cases, the calling routine + * has local copies of XLogCtl->Insert and/or XLogCtl->Insert->curridx, + * so these are passed as parameters instead of being fetched via XLogCtl. + */ + + /* Free space remaining in the current xlog page buffer */ + #define INSERT_FREESPACE(Insert) \ + (XLOG_BLCKSZ - ((Insert)->currpos - (char *) (Insert)->currpage)) + + /* Construct XLogRecPtr value for current insertion point */ + #define INSERT_RECPTR(recptr,Insert,curridx) \ + ( \ + (recptr).xlogid = XLogCtl->xlblocks[curridx].xlogid, \ + (recptr).xrecoff = \ + XLogCtl->xlblocks[curridx].xrecoff - INSERT_FREESPACE(Insert) \ + ) + + #define PrevBufIdx(idx) \ + (((idx) == 0) ? XLogCtl->XLogCacheBlck : ((idx) - 1)) + + #define NextBufIdx(idx) \ + (((idx) == XLogCtl->XLogCacheBlck) ? 0 : ((idx) + 1)) + + /* + * Private, possibly out-of-date copy of shared LogwrtResult. + * See discussion above. + */ + static XLogwrtResult LogwrtResult = {{0, 0}, {0, 0}}; + + /* + * openLogFile is -1 or a kernel FD for an open log file segment. + * When it's open, openLogOff is the current seek offset in the file. + * openLogId/openLogSeg identify the segment. These variables are only + * used to write the XLOG, and so will normally refer to the active segment. + */ + static int openLogFile = -1; + static uint32 openLogId = 0; + static uint32 openLogSeg = 0; + static uint32 openLogOff = 0; + + /* + * These variables are used similarly to the ones above, but for reading + * the XLOG. Note, however, that readOff generally represents the offset + * of the page just read, not the seek position of the FD itself, which + * will be just past that page. + */ + static int readFile = -1; + static uint32 readId = 0; + static uint32 readSeg = 0; + static uint32 readOff = 0; + + /* Buffer for currently read page (XLOG_BLCKSZ bytes) */ + static char *readBuf = NULL; + + /* Buffer for current ReadRecord result (expandable) */ + static char *readRecordBuf = NULL; + static uint32 readRecordBufSize = 0; + + /* + * Buffer for queued WAL records (fixed size) + * + * This buffer is used for holding WAL records and their LSNs. When the all WAL + * records of one WAL segment file are read, redo them and make the buffer + * empty. Therefore, twice of XLogSegSize, determined by the total size of WAL + * records and LSNs, must be enough for the buffer. + */ + #define RECORD_QUEUE_BUF_SIZE (XLogSegSize * 2) + static char *RecordQueueBuf = NULL; + static uint32 RecordQueueBufUsed = 0; + + /* State information for XLOG reading */ + static XLogRecPtr ReadRecPtr; /* start of last record read */ + static XLogRecPtr EndRecPtr; /* end+1 of last record read */ + static XLogRecord *nextRecord = NULL; + static TimeLineID lastPageTLI = 0; + + static bool InRedo = false; + + + static void XLogArchiveNotify(const char *xlog); + static void XLogArchiveNotifySeg(uint32 log, uint32 seg); + static bool XLogArchiveCheckDone(const char *xlog); + static bool XLogArchiveIsBusy(const char *xlog); + static void XLogArchiveCleanup(const char *xlog); + static void readRecoveryCommandFile(void); + static void exitArchiveRecovery(TimeLineID endTLI, + uint32 endLogId, uint32 endLogSeg); + static bool recoveryStopsHere(XLogRecord *record, bool *includeThis); + static void CheckPointGuts(XLogRecPtr checkPointRedo, int flags); + + static bool XLogCheckBuffer(XLogRecData *rdata, bool doPageWrites, + XLogRecPtr *lsn, BkpBlock *bkpb); + static bool AdvanceXLInsertBuffer(bool new_segment); + static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible, bool xlog_switch); + static int XLogFileInit(uint32 log, uint32 seg, + bool *use_existent, bool use_lock); + static bool InstallXLogFileSegment(uint32 *log, uint32 *seg, char *tmppath, + bool find_free, int *max_advance, + bool use_lock); + static int XLogFileOpen(uint32 log, uint32 seg); + static int XLogFileRead(uint32 log, uint32 seg, int emode); + static void XLogFileClose(void); + static bool RestoreArchivedFile(char *path, const char *xlogfname, + const char *recovername, off_t expectedSize); + static void PreallocXlogFiles(XLogRecPtr endptr); + static void RemoveOldXlogFiles(uint32 log, uint32 seg, XLogRecPtr endptr); + static void ValidateXLOGDirectoryStructure(void); + static void CleanupBackupHistory(void); + static XLogRecord *ReadRecord(XLogRecPtr *RecPtr, int emode); + static bool ValidXLOGHeader(XLogPageHeader hdr, int emode); + static XLogRecord *ReadCheckpointRecord(XLogRecPtr RecPtr, int whichChkpt); + static List *readTimeLineHistory(TimeLineID targetTLI); + static bool existsTimeLineHistory(TimeLineID probeTLI); + static TimeLineID findNewestTimeLine(TimeLineID startTLI); + static void writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI, + TimeLineID endTLI, + uint32 endLogId, uint32 endLogSeg); + static void WriteControlFile(void); + static void ReadControlFile(void); + static char *str_time(pg_time_t tnow); + #ifdef WAL_DEBUG + static void xlog_outrec(StringInfo buf, XLogRecord *record); + #endif + static void issue_xlog_fsync(void); + static void pg_start_backup_callback(int code, Datum arg); + static bool read_backup_label(XLogRecPtr *checkPointLoc, + XLogRecPtr *minRecoveryLoc); + static void rm_redo_error_callback(void *arg); + static int get_sync_bit(int method); + + static void PushRecord(XLogRecPtr lsn, XLogRecord *record); + static void PushReadAhead(XLogRecPtr lsn, XLogRecord *record); + static void RedoRecords(void); + + /* + * Insert an XLOG record having the specified RMID and info bytes, + * with the body of the record being the data chunk(s) described by + * the rdata chain (see xlog.h for notes about rdata). + * + * Returns XLOG pointer to end of record (beginning of next record). + * This can be used as LSN for data pages affected by the logged action. + * (LSN is the XLOG point up to which the XLOG must be flushed to disk + * before the data page can be written out. This implements the basic + * WAL rule "write the log before the data".) + * + * NB: this routine feels free to scribble on the XLogRecData structs, + * though not on the data they reference. This is OK since the XLogRecData + * structs are always just temporaries in the calling code. + */ + XLogRecPtr + XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata) + { + XLogCtlInsert *Insert = &XLogCtl->Insert; + XLogRecord *record; + XLogContRecord *contrecord; + XLogRecPtr RecPtr; + XLogRecPtr WriteRqst; + uint32 freespace; + int curridx; + XLogRecData *rdt; + Buffer dtbuf[XLR_MAX_BKP_BLOCKS]; + bool dtbuf_bkp[XLR_MAX_BKP_BLOCKS]; + BkpBlock dtbuf_xlg[XLR_MAX_BKP_BLOCKS]; + XLogRecPtr dtbuf_lsn[XLR_MAX_BKP_BLOCKS]; + XLogRecData dtbuf_rdt1[XLR_MAX_BKP_BLOCKS]; + XLogRecData dtbuf_rdt2[XLR_MAX_BKP_BLOCKS]; + XLogRecData dtbuf_rdt3[XLR_MAX_BKP_BLOCKS]; + pg_crc32 rdata_crc; + uint32 len, + write_len; + unsigned i; + bool updrqst; + bool doPageWrites; + bool isLogSwitch = (rmid == RM_XLOG_ID && info == XLOG_SWITCH); + + /* info's high bits are reserved for use by me */ + if (info & XLR_INFO_MASK) + elog(PANIC, "invalid xlog info mask %02X", info); + + TRACE_POSTGRESQL_XLOG_INSERT(rmid, info); + + /* + * In bootstrap mode, we don't actually log anything but XLOG resources; + * return a phony record pointer. + */ + if (IsBootstrapProcessingMode() && rmid != RM_XLOG_ID) + { + RecPtr.xlogid = 0; + RecPtr.xrecoff = SizeOfXLogLongPHD; /* start of 1st chkpt record */ + return RecPtr; + } + + /* + * Here we scan the rdata chain, determine which buffers must be backed + * up, and compute the CRC values for the data. Note that the record + * header isn't added into the CRC initially since we don't know the final + * length or info bits quite yet. Thus, the CRC will represent the CRC of + * the whole record in the order "rdata, then backup blocks, then record + * header". + * + * We may have to loop back to here if a race condition is detected below. + * We could prevent the race by doing all this work while holding the + * insert lock, but it seems better to avoid doing CRC calculations while + * holding the lock. This means we have to be careful about modifying the + * rdata chain until we know we aren't going to loop back again. The only + * change we allow ourselves to make earlier is to set rdt->data = NULL in + * chain items we have decided we will have to back up the whole buffer + * for. This is OK because we will certainly decide the same thing again + * for those items if we do it over; doing it here saves an extra pass + * over the chain later. + */ + begin:; + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + dtbuf[i] = InvalidBuffer; + dtbuf_bkp[i] = false; + } + + /* + * Decide if we need to do full-page writes in this XLOG record: true if + * full_page_writes is on or we have a PITR request for it. Since we + * don't yet have the insert lock, forcePageWrites could change under us, + * but we'll recheck it once we have the lock. + */ + doPageWrites = fullPageWrites || Insert->forcePageWrites; + + INIT_CRC32(rdata_crc); + len = 0; + for (rdt = rdata;;) + { + if (rdt->buffer == InvalidBuffer) + { + /* Simple data, just include it */ + len += rdt->len; + COMP_CRC32(rdata_crc, rdt->data, rdt->len); + } + else + { + /* Find info for buffer */ + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + if (rdt->buffer == dtbuf[i]) + { + /* Buffer already referenced by earlier chain item */ + if (dtbuf_bkp[i]) + rdt->data = NULL; + else if (rdt->data) + { + len += rdt->len; + COMP_CRC32(rdata_crc, rdt->data, rdt->len); + } + break; + } + if (dtbuf[i] == InvalidBuffer) + { + /* OK, put it in this slot */ + dtbuf[i] = rdt->buffer; + if (XLogCheckBuffer(rdt, doPageWrites, + &(dtbuf_lsn[i]), &(dtbuf_xlg[i]))) + { + dtbuf_bkp[i] = true; + rdt->data = NULL; + } + else if (rdt->data) + { + len += rdt->len; + COMP_CRC32(rdata_crc, rdt->data, rdt->len); + } + break; + } + } + if (i >= XLR_MAX_BKP_BLOCKS) + elog(PANIC, "can backup at most %d blocks per xlog record", + XLR_MAX_BKP_BLOCKS); + } + /* Break out of loop when rdt points to last chain item */ + if (rdt->next == NULL) + break; + rdt = rdt->next; + } + + /* + * Now add the backup block headers and data into the CRC + */ + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + if (dtbuf_bkp[i]) + { + BkpBlock *bkpb = &(dtbuf_xlg[i]); + char *page; + + COMP_CRC32(rdata_crc, + (char *) bkpb, + sizeof(BkpBlock)); + page = (char *) BufferGetBlock(dtbuf[i]); + if (bkpb->hole_length == 0) + { + COMP_CRC32(rdata_crc, + page, + BLCKSZ); + } + else + { + /* must skip the hole */ + COMP_CRC32(rdata_crc, + page, + bkpb->hole_offset); + COMP_CRC32(rdata_crc, + page + (bkpb->hole_offset + bkpb->hole_length), + BLCKSZ - (bkpb->hole_offset + bkpb->hole_length)); + } + } + } + + /* + * NOTE: We disallow len == 0 because it provides a useful bit of extra + * error checking in ReadRecord. This means that all callers of + * XLogInsert must supply at least some not-in-a-buffer data. However, we + * make an exception for XLOG SWITCH records because we don't want them to + * ever cross a segment boundary. + */ + if (len == 0 && !isLogSwitch) + elog(PANIC, "invalid xlog record length %u", len); + + START_CRIT_SECTION(); + + /* Now wait to get insert lock */ + LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); + + /* + * Check to see if my RedoRecPtr is out of date. If so, may have to go + * back and recompute everything. This can only happen just after a + * checkpoint, so it's better to be slow in this case and fast otherwise. + * + * If we aren't doing full-page writes then RedoRecPtr doesn't actually + * affect the contents of the XLOG record, so we'll update our local copy + * but not force a recomputation. + */ + if (!XLByteEQ(RedoRecPtr, Insert->RedoRecPtr)) + { + Assert(XLByteLT(RedoRecPtr, Insert->RedoRecPtr)); + RedoRecPtr = Insert->RedoRecPtr; + + if (doPageWrites) + { + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + if (dtbuf[i] == InvalidBuffer) + continue; + if (dtbuf_bkp[i] == false && + XLByteLE(dtbuf_lsn[i], RedoRecPtr)) + { + /* + * Oops, this buffer now needs to be backed up, but we + * didn't think so above. Start over. + */ + LWLockRelease(WALInsertLock); + END_CRIT_SECTION(); + goto begin; + } + } + } + } + + /* + * Also check to see if forcePageWrites was just turned on; if we weren't + * already doing full-page writes then go back and recompute. (If it was + * just turned off, we could recompute the record without full pages, but + * we choose not to bother.) + */ + if (Insert->forcePageWrites && !doPageWrites) + { + /* Oops, must redo it with full-page data */ + LWLockRelease(WALInsertLock); + END_CRIT_SECTION(); + goto begin; + } + + /* + * Make additional rdata chain entries for the backup blocks, so that we + * don't need to special-case them in the write loop. Note that we have + * now irrevocably changed the input rdata chain. At the exit of this + * loop, write_len includes the backup block data. + * + * Also set the appropriate info bits to show which buffers were backed + * up. The i'th XLR_SET_BKP_BLOCK bit corresponds to the i'th distinct + * buffer value (ignoring InvalidBuffer) appearing in the rdata chain. + */ + write_len = len; + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + BkpBlock *bkpb; + char *page; + + if (!dtbuf_bkp[i]) + continue; + + info |= XLR_SET_BKP_BLOCK(i); + + bkpb = &(dtbuf_xlg[i]); + page = (char *) BufferGetBlock(dtbuf[i]); + + rdt->next = &(dtbuf_rdt1[i]); + rdt = rdt->next; + + rdt->data = (char *) bkpb; + rdt->len = sizeof(BkpBlock); + write_len += sizeof(BkpBlock); + + rdt->next = &(dtbuf_rdt2[i]); + rdt = rdt->next; + + if (bkpb->hole_length == 0) + { + rdt->data = page; + rdt->len = BLCKSZ; + write_len += BLCKSZ; + rdt->next = NULL; + } + else + { + /* must skip the hole */ + rdt->data = page; + rdt->len = bkpb->hole_offset; + write_len += bkpb->hole_offset; + + rdt->next = &(dtbuf_rdt3[i]); + rdt = rdt->next; + + rdt->data = page + (bkpb->hole_offset + bkpb->hole_length); + rdt->len = BLCKSZ - (bkpb->hole_offset + bkpb->hole_length); + write_len += rdt->len; + rdt->next = NULL; + } + } + + /* + * If we backed up any full blocks and online backup is not in progress, + * mark the backup blocks as removable. This allows the WAL archiver to + * know whether it is safe to compress archived WAL data by transforming + * full-block records into the non-full-block format. + * + * Note: we could just set the flag whenever !forcePageWrites, but + * defining it like this leaves the info bit free for some potential other + * use in records without any backup blocks. + */ + if ((info & XLR_BKP_BLOCK_MASK) && !Insert->forcePageWrites) + info |= XLR_BKP_REMOVABLE; + + /* + * If there isn't enough space on the current XLOG page for a record + * header, advance to the next page (leaving the unused space as zeroes). + */ + updrqst = false; + freespace = INSERT_FREESPACE(Insert); + if (freespace < SizeOfXLogRecord) + { + updrqst = AdvanceXLInsertBuffer(false); + freespace = INSERT_FREESPACE(Insert); + } + + /* Compute record's XLOG location */ + curridx = Insert->curridx; + INSERT_RECPTR(RecPtr, Insert, curridx); + + /* + * If the record is an XLOG_SWITCH, and we are exactly at the start of a + * segment, we need not insert it (and don't want to because we'd like + * consecutive switch requests to be no-ops). Instead, make sure + * everything is written and flushed through the end of the prior segment, + * and return the prior segment's end address. + */ + if (isLogSwitch && + (RecPtr.xrecoff % XLogSegSize) == SizeOfXLogLongPHD) + { + /* We can release insert lock immediately */ + LWLockRelease(WALInsertLock); + + RecPtr.xrecoff -= SizeOfXLogLongPHD; + if (RecPtr.xrecoff == 0) + { + /* crossing a logid boundary */ + RecPtr.xlogid -= 1; + RecPtr.xrecoff = XLogFileSize; + } + + LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); + LogwrtResult = XLogCtl->Write.LogwrtResult; + if (!XLByteLE(RecPtr, LogwrtResult.Flush)) + { + XLogwrtRqst FlushRqst; + + FlushRqst.Write = RecPtr; + FlushRqst.Flush = RecPtr; + XLogWrite(FlushRqst, false, false); + } + LWLockRelease(WALWriteLock); + + END_CRIT_SECTION(); + + return RecPtr; + } + + /* Insert record header */ + + record = (XLogRecord *) Insert->currpos; + record->xl_prev = Insert->PrevRecord; + record->xl_xid = GetCurrentTransactionIdIfAny(); + record->xl_tot_len = SizeOfXLogRecord + write_len; + record->xl_len = len; /* doesn't include backup blocks */ + record->xl_info = info; + record->xl_rmid = rmid; + + /* Now we can finish computing the record's CRC */ + COMP_CRC32(rdata_crc, (char *) record + sizeof(pg_crc32), + SizeOfXLogRecord - sizeof(pg_crc32)); + FIN_CRC32(rdata_crc); + record->xl_crc = rdata_crc; + + #ifdef WAL_DEBUG + if (XLOG_DEBUG) + { + StringInfoData buf; + + initStringInfo(&buf); + appendStringInfo(&buf, "INSERT @ %X/%X: ", + RecPtr.xlogid, RecPtr.xrecoff); + xlog_outrec(&buf, record); + if (rdata->data != NULL) + { + appendStringInfo(&buf, " - "); + RmgrTable[record->xl_rmid].rm_desc(&buf, record->xl_info, rdata->data); + } + elog(LOG, "%s", buf.data); + pfree(buf.data); + } + #endif + + /* Record begin of record in appropriate places */ + ProcLastRecPtr = RecPtr; + Insert->PrevRecord = RecPtr; + + Insert->currpos += SizeOfXLogRecord; + freespace -= SizeOfXLogRecord; + + /* + * Append the data, including backup blocks if any + */ + while (write_len) + { + while (rdata->data == NULL) + rdata = rdata->next; + + if (freespace > 0) + { + if (rdata->len > freespace) + { + memcpy(Insert->currpos, rdata->data, freespace); + rdata->data += freespace; + rdata->len -= freespace; + write_len -= freespace; + } + else + { + memcpy(Insert->currpos, rdata->data, rdata->len); + freespace -= rdata->len; + write_len -= rdata->len; + Insert->currpos += rdata->len; + rdata = rdata->next; + continue; + } + } + + /* Use next buffer */ + updrqst = AdvanceXLInsertBuffer(false); + curridx = Insert->curridx; + /* Insert cont-record header */ + Insert->currpage->xlp_info |= XLP_FIRST_IS_CONTRECORD; + contrecord = (XLogContRecord *) Insert->currpos; + contrecord->xl_rem_len = write_len; + Insert->currpos += SizeOfXLogContRecord; + freespace = INSERT_FREESPACE(Insert); + } + + /* Ensure next record will be properly aligned */ + Insert->currpos = (char *) Insert->currpage + + MAXALIGN(Insert->currpos - (char *) Insert->currpage); + freespace = INSERT_FREESPACE(Insert); + + /* + * The recptr I return is the beginning of the *next* record. This will be + * stored as LSN for changed data pages... + */ + INSERT_RECPTR(RecPtr, Insert, curridx); + + /* + * If the record is an XLOG_SWITCH, we must now write and flush all the + * existing data, and then forcibly advance to the start of the next + * segment. It's not good to do this I/O while holding the insert lock, + * but there seems too much risk of confusion if we try to release the + * lock sooner. Fortunately xlog switch needn't be a high-performance + * operation anyway... + */ + if (isLogSwitch) + { + XLogCtlWrite *Write = &XLogCtl->Write; + XLogwrtRqst FlushRqst; + XLogRecPtr OldSegEnd; + + TRACE_POSTGRESQL_XLOG_SWITCH(); + + LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); + + /* + * Flush through the end of the page containing XLOG_SWITCH, and + * perform end-of-segment actions (eg, notifying archiver). + */ + WriteRqst = XLogCtl->xlblocks[curridx]; + FlushRqst.Write = WriteRqst; + FlushRqst.Flush = WriteRqst; + XLogWrite(FlushRqst, false, true); + + /* Set up the next buffer as first page of next segment */ + /* Note: AdvanceXLInsertBuffer cannot need to do I/O here */ + (void) AdvanceXLInsertBuffer(true); + + /* There should be no unwritten data */ + curridx = Insert->curridx; + Assert(curridx == Write->curridx); + + /* Compute end address of old segment */ + OldSegEnd = XLogCtl->xlblocks[curridx]; + OldSegEnd.xrecoff -= XLOG_BLCKSZ; + if (OldSegEnd.xrecoff == 0) + { + /* crossing a logid boundary */ + OldSegEnd.xlogid -= 1; + OldSegEnd.xrecoff = XLogFileSize; + } + + /* Make it look like we've written and synced all of old segment */ + LogwrtResult.Write = OldSegEnd; + LogwrtResult.Flush = OldSegEnd; + + /* + * Update shared-memory status --- this code should match XLogWrite + */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + xlogctl->LogwrtResult = LogwrtResult; + if (XLByteLT(xlogctl->LogwrtRqst.Write, LogwrtResult.Write)) + xlogctl->LogwrtRqst.Write = LogwrtResult.Write; + if (XLByteLT(xlogctl->LogwrtRqst.Flush, LogwrtResult.Flush)) + xlogctl->LogwrtRqst.Flush = LogwrtResult.Flush; + SpinLockRelease(&xlogctl->info_lck); + } + + Write->LogwrtResult = LogwrtResult; + + LWLockRelease(WALWriteLock); + + updrqst = false; /* done already */ + } + else + { + /* normal case, ie not xlog switch */ + + /* Need to update shared LogwrtRqst if some block was filled up */ + if (freespace < SizeOfXLogRecord) + { + /* curridx is filled and available for writing out */ + updrqst = true; + } + else + { + /* if updrqst already set, write through end of previous buf */ + curridx = PrevBufIdx(curridx); + } + WriteRqst = XLogCtl->xlblocks[curridx]; + } + + LWLockRelease(WALInsertLock); + + if (updrqst) + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + /* advance global request to include new block(s) */ + if (XLByteLT(xlogctl->LogwrtRqst.Write, WriteRqst)) + xlogctl->LogwrtRqst.Write = WriteRqst; + /* update local result copy while I have the chance */ + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease(&xlogctl->info_lck); + } + + XactLastRecEnd = RecPtr; + + END_CRIT_SECTION(); + + return RecPtr; + } + + /* + * Determine whether the buffer referenced by an XLogRecData item has to + * be backed up, and if so fill a BkpBlock struct for it. In any case + * save the buffer's LSN at *lsn. + */ + static bool + XLogCheckBuffer(XLogRecData *rdata, bool doPageWrites, + XLogRecPtr *lsn, BkpBlock *bkpb) + { + Page page; + + page = BufferGetPage(rdata->buffer); + + /* + * XXX We assume page LSN is first data on *every* page that can be passed + * to XLogInsert, whether it otherwise has the standard page layout or + * not. + */ + *lsn = PageGetLSN(page); + + if (doPageWrites && + XLByteLE(PageGetLSN(page), RedoRecPtr)) + { + /* + * The page needs to be backed up, so set up *bkpb + */ + BufferGetTag(rdata->buffer, &bkpb->node, &bkpb->fork, &bkpb->block); + + if (rdata->buffer_std) + { + /* Assume we can omit data between pd_lower and pd_upper */ + uint16 lower = ((PageHeader) page)->pd_lower; + uint16 upper = ((PageHeader) page)->pd_upper; + + if (lower >= SizeOfPageHeaderData && + upper > lower && + upper <= BLCKSZ) + { + bkpb->hole_offset = lower; + bkpb->hole_length = upper - lower; + } + else + { + /* No "hole" to compress out */ + bkpb->hole_offset = 0; + bkpb->hole_length = 0; + } + } + else + { + /* Not a standard page header, don't try to eliminate "hole" */ + bkpb->hole_offset = 0; + bkpb->hole_length = 0; + } + + return true; /* buffer requires backup */ + } + + return false; /* buffer does not need to be backed up */ + } + + /* + * XLogArchiveNotify + * + * Create an archive notification file + * + * The name of the notification file is the message that will be picked up + * by the archiver, e.g. we write 0000000100000001000000C6.ready + * and the archiver then knows to archive XLOGDIR/0000000100000001000000C6, + * then when complete, rename it to 0000000100000001000000C6.done + */ + static void + XLogArchiveNotify(const char *xlog) + { + char archiveStatusPath[MAXPGPATH]; + FILE *fd; + + /* insert an otherwise empty file called .ready */ + StatusFilePath(archiveStatusPath, xlog, ".ready"); + fd = AllocateFile(archiveStatusPath, "w"); + if (fd == NULL) + { + ereport(LOG, + (errcode_for_file_access(), + errmsg("could not create archive status file \"%s\": %m", + archiveStatusPath))); + return; + } + if (FreeFile(fd)) + { + ereport(LOG, + (errcode_for_file_access(), + errmsg("could not write archive status file \"%s\": %m", + archiveStatusPath))); + return; + } + + /* Notify archiver that it's got something to do */ + if (IsUnderPostmaster) + SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER); + } + + /* + * Convenience routine to notify using log/seg representation of filename + */ + static void + XLogArchiveNotifySeg(uint32 log, uint32 seg) + { + char xlog[MAXFNAMELEN]; + + XLogFileName(xlog, ThisTimeLineID, log, seg); + XLogArchiveNotify(xlog); + } + + /* + * XLogArchiveCheckDone + * + * This is called when we are ready to delete or recycle an old XLOG segment + * file or backup history file. If it is okay to delete it then return true. + * If it is not time to delete it, make sure a .ready file exists, and return + * false. + * + * If .done exists, then return true; else if .ready exists, + * then return false; else create .ready and return false. + * + * The reason we do things this way is so that if the original attempt to + * create .ready fails, we'll retry during subsequent checkpoints. + */ + static bool + XLogArchiveCheckDone(const char *xlog) + { + char archiveStatusPath[MAXPGPATH]; + struct stat stat_buf; + + /* Always deletable if archiving is off */ + if (!XLogArchivingActive()) + return true; + + /* First check for .done --- this means archiver is done with it */ + StatusFilePath(archiveStatusPath, xlog, ".done"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return true; + + /* check for .ready --- this means archiver is still busy with it */ + StatusFilePath(archiveStatusPath, xlog, ".ready"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return false; + + /* Race condition --- maybe archiver just finished, so recheck */ + StatusFilePath(archiveStatusPath, xlog, ".done"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return true; + + /* Retry creation of the .ready file */ + XLogArchiveNotify(xlog); + return false; + } + + /* + * XLogArchiveIsBusy + * + * Check to see if an XLOG segment file is still unarchived. + * This is almost but not quite the inverse of XLogArchiveCheckDone: in + * the first place we aren't chartered to recreate the .ready file, and + * in the second place we should consider that if the file is already gone + * then it's not busy. (This check is needed to handle the race condition + * that a checkpoint already deleted the no-longer-needed file.) + */ + static bool + XLogArchiveIsBusy(const char *xlog) + { + char archiveStatusPath[MAXPGPATH]; + struct stat stat_buf; + + /* First check for .done --- this means archiver is done with it */ + StatusFilePath(archiveStatusPath, xlog, ".done"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return false; + + /* check for .ready --- this means archiver is still busy with it */ + StatusFilePath(archiveStatusPath, xlog, ".ready"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return true; + + /* Race condition --- maybe archiver just finished, so recheck */ + StatusFilePath(archiveStatusPath, xlog, ".done"); + if (stat(archiveStatusPath, &stat_buf) == 0) + return false; + + /* + * Check to see if the WAL file has been removed by checkpoint, + * which implies it has already been archived, and explains why we + * can't see a status file for it. + */ + snprintf(archiveStatusPath, MAXPGPATH, XLOGDIR "/%s", xlog); + if (stat(archiveStatusPath, &stat_buf) != 0 && + errno == ENOENT) + return false; + + return true; + } + + /* + * XLogArchiveCleanup + * + * Cleanup archive notification file(s) for a particular xlog segment + */ + static void + XLogArchiveCleanup(const char *xlog) + { + char archiveStatusPath[MAXPGPATH]; + + /* Remove the .done file */ + StatusFilePath(archiveStatusPath, xlog, ".done"); + unlink(archiveStatusPath); + /* should we complain about failure? */ + + /* Remove the .ready file if present --- normally it shouldn't be */ + StatusFilePath(archiveStatusPath, xlog, ".ready"); + unlink(archiveStatusPath); + /* should we complain about failure? */ + } + + /* + * Advance the Insert state to the next buffer page, writing out the next + * buffer if it still contains unwritten data. + * + * If new_segment is TRUE then we set up the next buffer page as the first + * page of the next xlog segment file, possibly but not usually the next + * consecutive file page. + * + * The global LogwrtRqst.Write pointer needs to be advanced to include the + * just-filled page. If we can do this for free (without an extra lock), + * we do so here. Otherwise the caller must do it. We return TRUE if the + * request update still needs to be done, FALSE if we did it internally. + * + * Must be called with WALInsertLock held. + */ + static bool + AdvanceXLInsertBuffer(bool new_segment) + { + XLogCtlInsert *Insert = &XLogCtl->Insert; + XLogCtlWrite *Write = &XLogCtl->Write; + int nextidx = NextBufIdx(Insert->curridx); + bool update_needed = true; + XLogRecPtr OldPageRqstPtr; + XLogwrtRqst WriteRqst; + XLogRecPtr NewPageEndPtr; + XLogPageHeader NewPage; + + /* Use Insert->LogwrtResult copy if it's more fresh */ + if (XLByteLT(LogwrtResult.Write, Insert->LogwrtResult.Write)) + LogwrtResult = Insert->LogwrtResult; + + /* + * Get ending-offset of the buffer page we need to replace (this may be + * zero if the buffer hasn't been used yet). Fall through if it's already + * written out. + */ + OldPageRqstPtr = XLogCtl->xlblocks[nextidx]; + if (!XLByteLE(OldPageRqstPtr, LogwrtResult.Write)) + { + /* nope, got work to do... */ + XLogRecPtr FinishedPageRqstPtr; + + FinishedPageRqstPtr = XLogCtl->xlblocks[Insert->curridx]; + + /* Before waiting, get info_lck and update LogwrtResult */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + if (XLByteLT(xlogctl->LogwrtRqst.Write, FinishedPageRqstPtr)) + xlogctl->LogwrtRqst.Write = FinishedPageRqstPtr; + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease(&xlogctl->info_lck); + } + + update_needed = false; /* Did the shared-request update */ + + if (XLByteLE(OldPageRqstPtr, LogwrtResult.Write)) + { + /* OK, someone wrote it already */ + Insert->LogwrtResult = LogwrtResult; + } + else + { + /* Must acquire write lock */ + LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); + LogwrtResult = Write->LogwrtResult; + if (XLByteLE(OldPageRqstPtr, LogwrtResult.Write)) + { + /* OK, someone wrote it already */ + LWLockRelease(WALWriteLock); + Insert->LogwrtResult = LogwrtResult; + } + else + { + /* + * Have to write buffers while holding insert lock. This is + * not good, so only write as much as we absolutely must. + */ + TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_START(); + WriteRqst.Write = OldPageRqstPtr; + WriteRqst.Flush.xlogid = 0; + WriteRqst.Flush.xrecoff = 0; + XLogWrite(WriteRqst, false, false); + LWLockRelease(WALWriteLock); + Insert->LogwrtResult = LogwrtResult; + TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE(); + } + } + } + + /* + * Now the next buffer slot is free and we can set it up to be the next + * output page. + */ + NewPageEndPtr = XLogCtl->xlblocks[Insert->curridx]; + + if (new_segment) + { + /* force it to a segment start point */ + NewPageEndPtr.xrecoff += XLogSegSize - 1; + NewPageEndPtr.xrecoff -= NewPageEndPtr.xrecoff % XLogSegSize; + } + + if (NewPageEndPtr.xrecoff >= XLogFileSize) + { + /* crossing a logid boundary */ + NewPageEndPtr.xlogid += 1; + NewPageEndPtr.xrecoff = XLOG_BLCKSZ; + } + else + NewPageEndPtr.xrecoff += XLOG_BLCKSZ; + XLogCtl->xlblocks[nextidx] = NewPageEndPtr; + NewPage = (XLogPageHeader) (XLogCtl->pages + nextidx * (Size) XLOG_BLCKSZ); + + Insert->curridx = nextidx; + Insert->currpage = NewPage; + + Insert->currpos = ((char *) NewPage) +SizeOfXLogShortPHD; + + /* + * Be sure to re-zero the buffer so that bytes beyond what we've written + * will look like zeroes and not valid XLOG records... + */ + MemSet((char *) NewPage, 0, XLOG_BLCKSZ); + + /* + * Fill the new page's header + */ + NewPage ->xlp_magic = XLOG_PAGE_MAGIC; + + /* NewPage->xlp_info = 0; */ /* done by memset */ + NewPage ->xlp_tli = ThisTimeLineID; + NewPage ->xlp_pageaddr.xlogid = NewPageEndPtr.xlogid; + NewPage ->xlp_pageaddr.xrecoff = NewPageEndPtr.xrecoff - XLOG_BLCKSZ; + + /* + * If first page of an XLOG segment file, make it a long header. + */ + if ((NewPage->xlp_pageaddr.xrecoff % XLogSegSize) == 0) + { + XLogLongPageHeader NewLongPage = (XLogLongPageHeader) NewPage; + + NewLongPage->xlp_sysid = ControlFile->system_identifier; + NewLongPage->xlp_seg_size = XLogSegSize; + NewLongPage->xlp_xlog_blcksz = XLOG_BLCKSZ; + NewPage ->xlp_info |= XLP_LONG_HEADER; + + Insert->currpos = ((char *) NewPage) +SizeOfXLogLongPHD; + } + + return update_needed; + } + + /* + * Check whether we've consumed enough xlog space that a checkpoint is needed. + * + * Caller must have just finished filling the open log file (so that + * openLogId/openLogSeg are valid). We measure the distance from RedoRecPtr + * to the open log file and see if that exceeds CheckPointSegments. + * + * Note: it is caller's responsibility that RedoRecPtr is up-to-date. + */ + static bool + XLogCheckpointNeeded(void) + { + /* + * A straight computation of segment number could overflow 32 bits. Rather + * than assuming we have working 64-bit arithmetic, we compare the + * highest-order bits separately, and force a checkpoint immediately when + * they change. + */ + uint32 old_segno, + new_segno; + uint32 old_highbits, + new_highbits; + + old_segno = (RedoRecPtr.xlogid % XLogSegSize) * XLogSegsPerFile + + (RedoRecPtr.xrecoff / XLogSegSize); + old_highbits = RedoRecPtr.xlogid / XLogSegSize; + new_segno = (openLogId % XLogSegSize) * XLogSegsPerFile + openLogSeg; + new_highbits = openLogId / XLogSegSize; + if (new_highbits != old_highbits || + new_segno >= old_segno + (uint32) (CheckPointSegments - 1)) + return true; + return false; + } + + /* + * Write and/or fsync the log at least as far as WriteRqst indicates. + * + * If flexible == TRUE, we don't have to write as far as WriteRqst, but + * may stop at any convenient boundary (such as a cache or logfile boundary). + * This option allows us to avoid uselessly issuing multiple writes when a + * single one would do. + * + * If xlog_switch == TRUE, we are intending an xlog segment switch, so + * perform end-of-segment actions after writing the last page, even if + * it's not physically the end of its segment. (NB: this will work properly + * only if caller specifies WriteRqst == page-end and flexible == false, + * and there is some data to write.) + * + * Must be called with WALWriteLock held. + */ + static void + XLogWrite(XLogwrtRqst WriteRqst, bool flexible, bool xlog_switch) + { + XLogCtlWrite *Write = &XLogCtl->Write; + bool ispartialpage; + bool last_iteration; + bool finishing_seg; + bool use_existent; + int curridx; + int npages; + int startidx; + uint32 startoffset; + + /* We should always be inside a critical section here */ + Assert(CritSectionCount > 0); + + /* + * Update local LogwrtResult (caller probably did this already, but...) + */ + LogwrtResult = Write->LogwrtResult; + + /* + * Since successive pages in the xlog cache are consecutively allocated, + * we can usually gather multiple pages together and issue just one + * write() call. npages is the number of pages we have determined can be + * written together; startidx is the cache block index of the first one, + * and startoffset is the file offset at which it should go. The latter + * two variables are only valid when npages > 0, but we must initialize + * all of them to keep the compiler quiet. + */ + npages = 0; + startidx = 0; + startoffset = 0; + + /* + * Within the loop, curridx is the cache block index of the page to + * consider writing. We advance Write->curridx only after successfully + * writing pages. (Right now, this refinement is useless since we are + * going to PANIC if any error occurs anyway; but someday it may come in + * useful.) + */ + curridx = Write->curridx; + + while (XLByteLT(LogwrtResult.Write, WriteRqst.Write)) + { + /* + * Make sure we're not ahead of the insert process. This could happen + * if we're passed a bogus WriteRqst.Write that is past the end of the + * last page that's been initialized by AdvanceXLInsertBuffer. + */ + if (!XLByteLT(LogwrtResult.Write, XLogCtl->xlblocks[curridx])) + elog(PANIC, "xlog write request %X/%X is past end of log %X/%X", + LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff, + XLogCtl->xlblocks[curridx].xlogid, + XLogCtl->xlblocks[curridx].xrecoff); + + /* Advance LogwrtResult.Write to end of current buffer page */ + LogwrtResult.Write = XLogCtl->xlblocks[curridx]; + ispartialpage = XLByteLT(WriteRqst.Write, LogwrtResult.Write); + + if (!XLByteInPrevSeg(LogwrtResult.Write, openLogId, openLogSeg)) + { + /* + * Switch to new logfile segment. We cannot have any pending + * pages here (since we dump what we have at segment end). + */ + Assert(npages == 0); + if (openLogFile >= 0) + XLogFileClose(); + XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg); + + /* create/use new log file */ + use_existent = true; + openLogFile = XLogFileInit(openLogId, openLogSeg, + &use_existent, true); + openLogOff = 0; + } + + /* Make sure we have the current logfile open */ + if (openLogFile < 0) + { + XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg); + openLogFile = XLogFileOpen(openLogId, openLogSeg); + openLogOff = 0; + } + + /* Add current page to the set of pending pages-to-dump */ + if (npages == 0) + { + /* first of group */ + startidx = curridx; + startoffset = (LogwrtResult.Write.xrecoff - XLOG_BLCKSZ) % XLogSegSize; + } + npages++; + + /* + * Dump the set if this will be the last loop iteration, or if we are + * at the last page of the cache area (since the next page won't be + * contiguous in memory), or if we are at the end of the logfile + * segment. + */ + last_iteration = !XLByteLT(LogwrtResult.Write, WriteRqst.Write); + + finishing_seg = !ispartialpage && + (startoffset + npages * XLOG_BLCKSZ) >= XLogSegSize; + + if (last_iteration || + curridx == XLogCtl->XLogCacheBlck || + finishing_seg) + { + char *from; + Size nbytes; + + /* Need to seek in the file? */ + if (openLogOff != startoffset) + { + if (lseek(openLogFile, (off_t) startoffset, SEEK_SET) < 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not seek in log file %u, " + "segment %u to offset %u: %m", + openLogId, openLogSeg, startoffset))); + openLogOff = startoffset; + } + + /* OK to write the page(s) */ + from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ; + nbytes = npages * (Size) XLOG_BLCKSZ; + errno = 0; + if (write(openLogFile, from, nbytes) != nbytes) + { + /* if write didn't set errno, assume no disk space */ + if (errno == 0) + errno = ENOSPC; + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not write to log file %u, segment %u " + "at offset %u, length %lu: %m", + openLogId, openLogSeg, + openLogOff, (unsigned long) nbytes))); + } + + /* Update state for write */ + openLogOff += nbytes; + Write->curridx = ispartialpage ? curridx : NextBufIdx(curridx); + npages = 0; + + /* + * If we just wrote the whole last page of a logfile segment, + * fsync the segment immediately. This avoids having to go back + * and re-open prior segments when an fsync request comes along + * later. Doing it here ensures that one and only one backend will + * perform this fsync. + * + * We also do this if this is the last page written for an xlog + * switch. + * + * This is also the right place to notify the Archiver that the + * segment is ready to copy to archival storage, and to update the + * timer for archive_timeout, and to signal for a checkpoint if + * too many logfile segments have been used since the last + * checkpoint. + */ + if (finishing_seg || (xlog_switch && last_iteration)) + { + issue_xlog_fsync(); + LogwrtResult.Flush = LogwrtResult.Write; /* end of page */ + + if (XLogArchivingActive()) + XLogArchiveNotifySeg(openLogId, openLogSeg); + + Write->lastSegSwitchTime = (pg_time_t) time(NULL); + + /* + * Signal bgwriter to start a checkpoint if we've consumed too + * much xlog since the last one. For speed, we first check + * using the local copy of RedoRecPtr, which might be out of + * date; if it looks like a checkpoint is needed, forcibly + * update RedoRecPtr and recheck. + */ + if (IsUnderPostmaster && + XLogCheckpointNeeded()) + { + (void) GetRedoRecPtr(); + if (XLogCheckpointNeeded()) + RequestCheckpoint(CHECKPOINT_CAUSE_XLOG); + } + } + } + + if (ispartialpage) + { + /* Only asked to write a partial page */ + LogwrtResult.Write = WriteRqst.Write; + break; + } + curridx = NextBufIdx(curridx); + + /* If flexible, break out of loop as soon as we wrote something */ + if (flexible && npages == 0) + break; + } + + Assert(npages == 0); + Assert(curridx == Write->curridx); + + /* + * If asked to flush, do so + */ + if (XLByteLT(LogwrtResult.Flush, WriteRqst.Flush) && + XLByteLT(LogwrtResult.Flush, LogwrtResult.Write)) + { + /* + * Could get here without iterating above loop, in which case we might + * have no open file or the wrong one. However, we do not need to + * fsync more than one file. + */ + if (sync_method != SYNC_METHOD_OPEN && + sync_method != SYNC_METHOD_OPEN_DSYNC) + { + if (openLogFile >= 0 && + !XLByteInPrevSeg(LogwrtResult.Write, openLogId, openLogSeg)) + XLogFileClose(); + if (openLogFile < 0) + { + XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg); + openLogFile = XLogFileOpen(openLogId, openLogSeg); + openLogOff = 0; + } + issue_xlog_fsync(); + } + LogwrtResult.Flush = LogwrtResult.Write; + } + + /* + * Update shared-memory status + * + * We make sure that the shared 'request' values do not fall behind the + * 'result' values. This is not absolutely essential, but it saves some + * code in a couple of places. + */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + xlogctl->LogwrtResult = LogwrtResult; + if (XLByteLT(xlogctl->LogwrtRqst.Write, LogwrtResult.Write)) + xlogctl->LogwrtRqst.Write = LogwrtResult.Write; + if (XLByteLT(xlogctl->LogwrtRqst.Flush, LogwrtResult.Flush)) + xlogctl->LogwrtRqst.Flush = LogwrtResult.Flush; + SpinLockRelease(&xlogctl->info_lck); + } + + Write->LogwrtResult = LogwrtResult; + } + + /* + * Record the LSN for an asynchronous transaction commit. + * (This should not be called for aborts, nor for synchronous commits.) + */ + void + XLogSetAsyncCommitLSN(XLogRecPtr asyncCommitLSN) + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + if (XLByteLT(xlogctl->asyncCommitLSN, asyncCommitLSN)) + xlogctl->asyncCommitLSN = asyncCommitLSN; + SpinLockRelease(&xlogctl->info_lck); + } + + /* + * Ensure that all XLOG data through the given position is flushed to disk. + * + * NOTE: this differs from XLogWrite mainly in that the WALWriteLock is not + * already held, and we try to avoid acquiring it if possible. + */ + void + XLogFlush(XLogRecPtr record) + { + XLogRecPtr WriteRqstPtr; + XLogwrtRqst WriteRqst; + + /* Disabled during REDO */ + if (InRedo) + return; + + /* Quick exit if already known flushed */ + if (XLByteLE(record, LogwrtResult.Flush)) + return; + + #ifdef WAL_DEBUG + if (XLOG_DEBUG) + elog(LOG, "xlog flush request %X/%X; write %X/%X; flush %X/%X", + record.xlogid, record.xrecoff, + LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff, + LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff); + #endif + + START_CRIT_SECTION(); + + /* + * Since fsync is usually a horribly expensive operation, we try to + * piggyback as much data as we can on each fsync: if we see any more data + * entered into the xlog buffer, we'll write and fsync that too, so that + * the final value of LogwrtResult.Flush is as large as possible. This + * gives us some chance of avoiding another fsync immediately after. + */ + + /* initialize to given target; may increase below */ + WriteRqstPtr = record; + + /* read LogwrtResult and update local state */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + if (XLByteLT(WriteRqstPtr, xlogctl->LogwrtRqst.Write)) + WriteRqstPtr = xlogctl->LogwrtRqst.Write; + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease(&xlogctl->info_lck); + } + + /* done already? */ + if (!XLByteLE(record, LogwrtResult.Flush)) + { + /* now wait for the write lock */ + LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); + LogwrtResult = XLogCtl->Write.LogwrtResult; + if (!XLByteLE(record, LogwrtResult.Flush)) + { + /* try to write/flush later additions to XLOG as well */ + if (LWLockConditionalAcquire(WALInsertLock, LW_EXCLUSIVE)) + { + XLogCtlInsert *Insert = &XLogCtl->Insert; + uint32 freespace = INSERT_FREESPACE(Insert); + + if (freespace < SizeOfXLogRecord) /* buffer is full */ + WriteRqstPtr = XLogCtl->xlblocks[Insert->curridx]; + else + { + WriteRqstPtr = XLogCtl->xlblocks[Insert->curridx]; + WriteRqstPtr.xrecoff -= freespace; + } + LWLockRelease(WALInsertLock); + WriteRqst.Write = WriteRqstPtr; + WriteRqst.Flush = WriteRqstPtr; + } + else + { + WriteRqst.Write = WriteRqstPtr; + WriteRqst.Flush = record; + } + XLogWrite(WriteRqst, false, false); + } + LWLockRelease(WALWriteLock); + } + + END_CRIT_SECTION(); + + /* + * If we still haven't flushed to the request point then we have a + * problem; most likely, the requested flush point is past end of XLOG. + * This has been seen to occur when a disk page has a corrupted LSN. + * + * Formerly we treated this as a PANIC condition, but that hurts the + * system's robustness rather than helping it: we do not want to take down + * the whole system due to corruption on one data page. In particular, if + * the bad page is encountered again during recovery then we would be + * unable to restart the database at all! (This scenario has actually + * happened in the field several times with 7.1 releases. Note that we + * cannot get here while InRedo is true, but if the bad page is brought in + * and marked dirty during recovery then CreateCheckPoint will try to + * flush it at the end of recovery.) + * + * The current approach is to ERROR under normal conditions, but only + * WARNING during recovery, so that the system can be brought up even if + * there's a corrupt LSN. Note that for calls from xact.c, the ERROR will + * be promoted to PANIC since xact.c calls this routine inside a critical + * section. However, calls from bufmgr.c are not within critical sections + * and so we will not force a restart for a bad LSN on a data page. + */ + if (XLByteLT(LogwrtResult.Flush, record)) + elog(InRecovery ? WARNING : ERROR, + "xlog flush request %X/%X is not satisfied --- flushed only to %X/%X", + record.xlogid, record.xrecoff, + LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff); + } + + /* + * Flush xlog, but without specifying exactly where to flush to. + * + * We normally flush only completed blocks; but if there is nothing to do on + * that basis, we check for unflushed async commits in the current incomplete + * block, and flush through the latest one of those. Thus, if async commits + * are not being used, we will flush complete blocks only. We can guarantee + * that async commits reach disk after at most three cycles; normally only + * one or two. (We allow XLogWrite to write "flexibly", meaning it can stop + * at the end of the buffer ring; this makes a difference only with very high + * load or long wal_writer_delay, but imposes one extra cycle for the worst + * case for async commits.) + * + * This routine is invoked periodically by the background walwriter process. + */ + void + XLogBackgroundFlush(void) + { + XLogRecPtr WriteRqstPtr; + bool flexible = true; + + /* read LogwrtResult and update local state */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + LogwrtResult = xlogctl->LogwrtResult; + WriteRqstPtr = xlogctl->LogwrtRqst.Write; + SpinLockRelease(&xlogctl->info_lck); + } + + /* back off to last completed page boundary */ + WriteRqstPtr.xrecoff -= WriteRqstPtr.xrecoff % XLOG_BLCKSZ; + + /* if we have already flushed that far, consider async commit records */ + if (XLByteLE(WriteRqstPtr, LogwrtResult.Flush)) + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + WriteRqstPtr = xlogctl->asyncCommitLSN; + SpinLockRelease(&xlogctl->info_lck); + flexible = false; /* ensure it all gets written */ + } + + /* Done if already known flushed */ + if (XLByteLE(WriteRqstPtr, LogwrtResult.Flush)) + return; + + #ifdef WAL_DEBUG + if (XLOG_DEBUG) + elog(LOG, "xlog bg flush request %X/%X; write %X/%X; flush %X/%X", + WriteRqstPtr.xlogid, WriteRqstPtr.xrecoff, + LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff, + LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff); + #endif + + START_CRIT_SECTION(); + + /* now wait for the write lock */ + LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); + LogwrtResult = XLogCtl->Write.LogwrtResult; + if (!XLByteLE(WriteRqstPtr, LogwrtResult.Flush)) + { + XLogwrtRqst WriteRqst; + + WriteRqst.Write = WriteRqstPtr; + WriteRqst.Flush = WriteRqstPtr; + XLogWrite(WriteRqst, flexible, false); + } + LWLockRelease(WALWriteLock); + + END_CRIT_SECTION(); + } + + /* + * Flush any previous asynchronously-committed transactions' commit records. + * + * NOTE: it is unwise to assume that this provides any strong guarantees. + * In particular, because of the inexact LSN bookkeeping used by clog.c, + * we cannot assume that hint bits will be settable for these transactions. + */ + void + XLogAsyncCommitFlush(void) + { + XLogRecPtr WriteRqstPtr; + + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + WriteRqstPtr = xlogctl->asyncCommitLSN; + SpinLockRelease(&xlogctl->info_lck); + + XLogFlush(WriteRqstPtr); + } + + /* + * Test whether XLOG data has been flushed up to (at least) the given position. + * + * Returns true if a flush is still needed. (It may be that someone else + * is already in process of flushing that far, however.) + */ + bool + XLogNeedsFlush(XLogRecPtr record) + { + /* Quick exit if already known flushed */ + if (XLByteLE(record, LogwrtResult.Flush)) + return false; + + /* read LogwrtResult and update local state */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease(&xlogctl->info_lck); + } + + /* check again */ + if (XLByteLE(record, LogwrtResult.Flush)) + return false; + + return true; + } + + /* + * Create a new XLOG file segment, or open a pre-existing one. + * + * log, seg: identify segment to be created/opened. + * + * *use_existent: if TRUE, OK to use a pre-existing file (else, any + * pre-existing file will be deleted). On return, TRUE if a pre-existing + * file was used. + * + * use_lock: if TRUE, acquire ControlFileLock while moving file into + * place. This should be TRUE except during bootstrap log creation. The + * caller must *not* hold the lock at call. + * + * Returns FD of opened file. + * + * Note: errors here are ERROR not PANIC because we might or might not be + * inside a critical section (eg, during checkpoint there is no reason to + * take down the system on failure). They will promote to PANIC if we are + * in a critical section. + */ + static int + XLogFileInit(uint32 log, uint32 seg, + bool *use_existent, bool use_lock) + { + char path[MAXPGPATH]; + char tmppath[MAXPGPATH]; + char *zbuffer; + uint32 installed_log; + uint32 installed_seg; + int max_advance; + int fd; + int nbytes; + + XLogFilePath(path, ThisTimeLineID, log, seg); + + /* + * Try to use existent file (checkpoint maker may have created it already) + */ + if (*use_existent) + { + fd = BasicOpenFile(path, O_RDWR | PG_BINARY | get_sync_bit(sync_method), + S_IRUSR | S_IWUSR); + if (fd < 0) + { + if (errno != ENOENT) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open file \"%s\" (log file %u, segment %u): %m", + path, log, seg))); + } + else + return fd; + } + + /* + * Initialize an empty (all zeroes) segment. NOTE: it is possible that + * another process is doing the same thing. If so, we will end up + * pre-creating an extra log segment. That seems OK, and better than + * holding the lock throughout this lengthy process. + */ + elog(DEBUG2, "creating and filling new WAL file"); + + snprintf(tmppath, MAXPGPATH, XLOGDIR "/xlogtemp.%d", (int) getpid()); + + unlink(tmppath); + + /* do not use get_sync_bit() here --- want to fsync only at end of fill */ + fd = BasicOpenFile(tmppath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not create file \"%s\": %m", tmppath))); + + /* + * Zero-fill the file. We have to do this the hard way to ensure that all + * the file space has really been allocated --- on platforms that allow + * "holes" in files, just seeking to the end doesn't allocate intermediate + * space. This way, we know that we have all the space and (after the + * fsync below) that all the indirect blocks are down on disk. Therefore, + * fdatasync(2) or O_DSYNC will be sufficient to sync future writes to the + * log file. + * + * Note: palloc zbuffer, instead of just using a local char array, to + * ensure it is reasonably well-aligned; this may save a few cycles + * transferring data to the kernel. + */ + zbuffer = (char *) palloc0(XLOG_BLCKSZ); + for (nbytes = 0; nbytes < XLogSegSize; nbytes += XLOG_BLCKSZ) + { + errno = 0; + if ((int) write(fd, zbuffer, XLOG_BLCKSZ) != (int) XLOG_BLCKSZ) + { + int save_errno = errno; + + /* + * If we fail to make the file, delete it to release disk space + */ + unlink(tmppath); + /* if write didn't set errno, assume problem is no disk space */ + errno = save_errno ? save_errno : ENOSPC; + + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write to file \"%s\": %m", tmppath))); + } + } + pfree(zbuffer); + + if (pg_fsync(fd) != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not fsync file \"%s\": %m", tmppath))); + + if (close(fd)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not close file \"%s\": %m", tmppath))); + + /* + * Now move the segment into place with its final name. + * + * If caller didn't want to use a pre-existing file, get rid of any + * pre-existing file. Otherwise, cope with possibility that someone else + * has created the file while we were filling ours: if so, use ours to + * pre-create a future log segment. + */ + installed_log = log; + installed_seg = seg; + max_advance = XLOGfileslop; + if (!InstallXLogFileSegment(&installed_log, &installed_seg, tmppath, + *use_existent, &max_advance, + use_lock)) + { + /* No need for any more future segments... */ + unlink(tmppath); + } + + elog(DEBUG2, "done creating and filling new WAL file"); + + /* Set flag to tell caller there was no existent file */ + *use_existent = false; + + /* Now open original target segment (might not be file I just made) */ + fd = BasicOpenFile(path, O_RDWR | PG_BINARY | get_sync_bit(sync_method), + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open file \"%s\" (log file %u, segment %u): %m", + path, log, seg))); + + return fd; + } + + /* + * Create a new XLOG file segment by copying a pre-existing one. + * + * log, seg: identify segment to be created. + * + * srcTLI, srclog, srcseg: identify segment to be copied (could be from + * a different timeline) + * + * Currently this is only used during recovery, and so there are no locking + * considerations. But we should be just as tense as XLogFileInit to avoid + * emplacing a bogus file. + */ + static void + XLogFileCopy(uint32 log, uint32 seg, + TimeLineID srcTLI, uint32 srclog, uint32 srcseg) + { + char path[MAXPGPATH]; + char tmppath[MAXPGPATH]; + char buffer[XLOG_BLCKSZ]; + int srcfd; + int fd; + int nbytes; + + /* + * Open the source file + */ + XLogFilePath(path, srcTLI, srclog, srcseg); + srcfd = BasicOpenFile(path, O_RDONLY | PG_BINARY, 0); + if (srcfd < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open file \"%s\": %m", path))); + + /* + * Copy into a temp file name. + */ + snprintf(tmppath, MAXPGPATH, XLOGDIR "/xlogtemp.%d", (int) getpid()); + + unlink(tmppath); + + /* do not use get_sync_bit() here --- want to fsync only at end of fill */ + fd = BasicOpenFile(tmppath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not create file \"%s\": %m", tmppath))); + + /* + * Do the data copying. + */ + for (nbytes = 0; nbytes < XLogSegSize; nbytes += sizeof(buffer)) + { + errno = 0; + if ((int) read(srcfd, buffer, sizeof(buffer)) != (int) sizeof(buffer)) + { + if (errno != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", path))); + else + ereport(ERROR, + (errmsg("not enough data in file \"%s\"", path))); + } + errno = 0; + if ((int) write(fd, buffer, sizeof(buffer)) != (int) sizeof(buffer)) + { + int save_errno = errno; + + /* + * If we fail to make the file, delete it to release disk space + */ + unlink(tmppath); + /* if write didn't set errno, assume problem is no disk space */ + errno = save_errno ? save_errno : ENOSPC; + + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write to file \"%s\": %m", tmppath))); + } + } + + if (pg_fsync(fd) != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not fsync file \"%s\": %m", tmppath))); + + if (close(fd)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not close file \"%s\": %m", tmppath))); + + close(srcfd); + + /* + * Now move the segment into place with its final name. + */ + if (!InstallXLogFileSegment(&log, &seg, tmppath, false, NULL, false)) + elog(ERROR, "InstallXLogFileSegment should not have failed"); + } + + /* + * Install a new XLOG segment file as a current or future log segment. + * + * This is used both to install a newly-created segment (which has a temp + * filename while it's being created) and to recycle an old segment. + * + * *log, *seg: identify segment to install as (or first possible target). + * When find_free is TRUE, these are modified on return to indicate the + * actual installation location or last segment searched. + * + * tmppath: initial name of file to install. It will be renamed into place. + * + * find_free: if TRUE, install the new segment at the first empty log/seg + * number at or after the passed numbers. If FALSE, install the new segment + * exactly where specified, deleting any existing segment file there. + * + * *max_advance: maximum number of log/seg slots to advance past the starting + * point. Fail if no free slot is found in this range. On return, reduced + * by the number of slots skipped over. (Irrelevant, and may be NULL, + * when find_free is FALSE.) + * + * use_lock: if TRUE, acquire ControlFileLock while moving file into + * place. This should be TRUE except during bootstrap log creation. The + * caller must *not* hold the lock at call. + * + * Returns TRUE if file installed, FALSE if not installed because of + * exceeding max_advance limit. On Windows, we also return FALSE if we + * can't rename the file into place because someone's got it open. + * (Any other kind of failure causes ereport().) + */ + static bool + InstallXLogFileSegment(uint32 *log, uint32 *seg, char *tmppath, + bool find_free, int *max_advance, + bool use_lock) + { + char path[MAXPGPATH]; + struct stat stat_buf; + + XLogFilePath(path, ThisTimeLineID, *log, *seg); + + /* + * We want to be sure that only one process does this at a time. + */ + if (use_lock) + LWLockAcquire(ControlFileLock, LW_EXCLUSIVE); + + if (!find_free) + { + /* Force installation: get rid of any pre-existing segment file */ + unlink(path); + } + else + { + /* Find a free slot to put it in */ + while (stat(path, &stat_buf) == 0) + { + if (*max_advance <= 0) + { + /* Failed to find a free slot within specified range */ + if (use_lock) + LWLockRelease(ControlFileLock); + return false; + } + NextLogSeg(*log, *seg); + (*max_advance)--; + XLogFilePath(path, ThisTimeLineID, *log, *seg); + } + } + + /* + * Prefer link() to rename() here just to be really sure that we don't + * overwrite an existing logfile. However, there shouldn't be one, so + * rename() is an acceptable substitute except for the truly paranoid. + */ + #if HAVE_WORKING_LINK + if (link(tmppath, path) < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not link file \"%s\" to \"%s\" (initialization of log file %u, segment %u): %m", + tmppath, path, *log, *seg))); + unlink(tmppath); + #else + if (rename(tmppath, path) < 0) + { + #ifdef WIN32 + #if !defined(__CYGWIN__) + if (GetLastError() == ERROR_ACCESS_DENIED) + #else + if (errno == EACCES) + #endif + { + if (use_lock) + LWLockRelease(ControlFileLock); + return false; + } + #endif /* WIN32 */ + + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\" (initialization of log file %u, segment %u): %m", + tmppath, path, *log, *seg))); + } + #endif + + if (use_lock) + LWLockRelease(ControlFileLock); + + return true; + } + + /* + * Open a pre-existing logfile segment for writing. + */ + static int + XLogFileOpen(uint32 log, uint32 seg) + { + char path[MAXPGPATH]; + int fd; + + XLogFilePath(path, ThisTimeLineID, log, seg); + + fd = BasicOpenFile(path, O_RDWR | PG_BINARY | get_sync_bit(sync_method), + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not open file \"%s\" (log file %u, segment %u): %m", + path, log, seg))); + + return fd; + } + + /* + * Open a logfile segment for reading (during recovery). + */ + static int + XLogFileRead(uint32 log, uint32 seg, int emode) + { + char path[MAXPGPATH]; + char xlogfname[MAXFNAMELEN]; + char activitymsg[MAXFNAMELEN + 16]; + ListCell *cell; + int fd; + + ereport(DEBUG1, (errmsg("XLOG switch to %X/%X", log, seg))); + + /* + * Loop looking for a suitable timeline ID: we might need to read any of + * the timelines listed in expectedTLIs. + * + * We expect curFileTLI on entry to be the TLI of the preceding file in + * sequence, or 0 if there was no predecessor. We do not allow curFileTLI + * to go backwards; this prevents us from picking up the wrong file when a + * parent timeline extends to higher segment numbers than the child we + * want to read. + */ + foreach(cell, expectedTLIs) + { + TimeLineID tli = (TimeLineID) lfirst_int(cell); + + if (tli < curFileTLI) + break; /* don't bother looking at too-old TLIs */ + + XLogFileName(xlogfname, tli, log, seg); + + if (InArchiveRecovery) + { + /* + * Wait until next WAL segment file. It might takes long time. + * Therefore, redo with stored WAL records and LSNs here. + */ + ereport(DEBUG1, (errmsg("XLOG will be switched"))); + RedoRecords(); + + /* Report recovery progress in PS display */ + snprintf(activitymsg, sizeof(activitymsg), "waiting for %s", + xlogfname); + set_ps_display(activitymsg, false); + + restoredFromArchive = RestoreArchivedFile(path, xlogfname, + "RECOVERYXLOG", + XLogSegSize); + } + else + XLogFilePath(path, tli, log, seg); + + fd = BasicOpenFile(path, O_RDONLY | PG_BINARY, 0); + if (fd >= 0) + { + /* Success! */ + curFileTLI = tli; + + /* Report recovery progress in PS display */ + snprintf(activitymsg, sizeof(activitymsg), "recovering %s", + xlogfname); + set_ps_display(activitymsg, false); + + return fd; + } + if (errno != ENOENT) /* unexpected failure? */ + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not open file \"%s\" (log file %u, segment %u): %m", + path, log, seg))); + } + + /* Couldn't find it. For simplicity, complain about front timeline */ + XLogFilePath(path, recoveryTargetTLI, log, seg); + errno = ENOENT; + ereport(emode, + (errcode_for_file_access(), + errmsg("could not open file \"%s\" (log file %u, segment %u): %m", + path, log, seg))); + return -1; + } + + /* + * Close the current logfile segment for writing. + */ + static void + XLogFileClose(void) + { + Assert(openLogFile >= 0); + + /* + * WAL segment files will not be re-read in normal operation, so we advise + * the OS to release any cached pages. But do not do so if WAL archiving + * is active, because archiver process could use the cache to read the WAL + * segment. Also, don't bother with it if we are using O_DIRECT, since + * the kernel is presumably not caching in that case. + */ + #if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED) + if (!XLogArchivingActive() && + (get_sync_bit(sync_method) & PG_O_DIRECT) == 0) + (void) posix_fadvise(openLogFile, 0, 0, POSIX_FADV_DONTNEED); + #endif + + if (close(openLogFile)) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not close log file %u, segment %u: %m", + openLogId, openLogSeg))); + openLogFile = -1; + } + + /* + * Attempt to retrieve the specified file from off-line archival storage. + * If successful, fill "path" with its complete path (note that this will be + * a temp file name that doesn't follow the normal naming convention), and + * return TRUE. + * + * If not successful, fill "path" with the name of the normal on-line file + * (which may or may not actually exist, but we'll try to use it), and return + * FALSE. + * + * For fixed-size files, the caller may pass the expected size as an + * additional crosscheck on successful recovery. If the file size is not + * known, set expectedSize = 0. + */ + static bool + RestoreArchivedFile(char *path, const char *xlogfname, + const char *recovername, off_t expectedSize) + { + char xlogpath[MAXPGPATH]; + char xlogRestoreCmd[MAXPGPATH]; + char lastRestartPointFname[MAXPGPATH]; + char *dp; + char *endp; + const char *sp; + int rc; + bool signaled; + struct stat stat_buf; + uint32 restartLog; + uint32 restartSeg; + + /* + * When doing archive recovery, we always prefer an archived log file even + * if a file of the same name exists in XLOGDIR. The reason is that the + * file in XLOGDIR could be an old, un-filled or partly-filled version + * that was copied and restored as part of backing up $PGDATA. + * + * We could try to optimize this slightly by checking the local copy + * lastchange timestamp against the archived copy, but we have no API to + * do this, nor can we guarantee that the lastchange timestamp was + * preserved correctly when we copied to archive. Our aim is robustness, + * so we elect not to do this. + * + * If we cannot obtain the log file from the archive, however, we will try + * to use the XLOGDIR file if it exists. This is so that we can make use + * of log segments that weren't yet transferred to the archive. + * + * Notice that we don't actually overwrite any files when we copy back + * from archive because the recoveryRestoreCommand may inadvertently + * restore inappropriate xlogs, or they may be corrupt, so we may wish to + * fallback to the segments remaining in current XLOGDIR later. The + * copy-from-archive filename is always the same, ensuring that we don't + * run out of disk space on long recoveries. + */ + snprintf(xlogpath, MAXPGPATH, XLOGDIR "/%s", recovername); + + /* + * Make sure there is no existing file named recovername. + */ + if (stat(xlogpath, &stat_buf) != 0) + { + if (errno != ENOENT) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not stat file \"%s\": %m", + xlogpath))); + } + else + { + if (unlink(xlogpath) != 0) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not remove file \"%s\": %m", + xlogpath))); + } + + /* + * Calculate the archive file cutoff point for use during log shipping + * replication. All files earlier than this point can be deleted + * from the archive, though there is no requirement to do so. + * + * We initialise this with the filename of an InvalidXLogRecPtr, which + * will prevent the deletion of any WAL files from the archive + * because of the alphabetic sorting property of WAL filenames. + * + * Once we have successfully located the redo pointer of the checkpoint + * from which we start recovery we never request a file prior to the redo + * pointer of the last restartpoint. When redo begins we know that we + * have successfully located it, so there is no need for additional + * status flags to signify the point when we can begin deleting WAL files + * from the archive. + */ + if (InRedo) + { + XLByteToSeg(ControlFile->checkPointCopy.redo, + restartLog, restartSeg); + XLogFileName(lastRestartPointFname, + ControlFile->checkPointCopy.ThisTimeLineID, + restartLog, restartSeg); + /* we shouldn't need anything earlier than last restart point */ + Assert(strcmp(lastRestartPointFname, xlogfname) <= 0); + } + else + XLogFileName(lastRestartPointFname, 0, 0, 0); + + /* + * construct the command to be executed + */ + dp = xlogRestoreCmd; + endp = xlogRestoreCmd + MAXPGPATH - 1; + *endp = '\0'; + + for (sp = recoveryRestoreCommand; *sp; sp++) + { + if (*sp == '%') + { + switch (sp[1]) + { + case 'p': + /* %p: relative path of target file */ + sp++; + StrNCpy(dp, xlogpath, endp - dp); + make_native_path(dp); + dp += strlen(dp); + break; + case 'f': + /* %f: filename of desired file */ + sp++; + StrNCpy(dp, xlogfname, endp - dp); + dp += strlen(dp); + break; + case 'r': + /* %r: filename of last restartpoint */ + sp++; + StrNCpy(dp, lastRestartPointFname, endp - dp); + dp += strlen(dp); + break; + case '%': + /* convert %% to a single % */ + sp++; + if (dp < endp) + *dp++ = *sp; + break; + default: + /* otherwise treat the % as not special */ + if (dp < endp) + *dp++ = *sp; + break; + } + } + else + { + if (dp < endp) + *dp++ = *sp; + } + } + *dp = '\0'; + + ereport(DEBUG3, + (errmsg_internal("executing restore command \"%s\"", + xlogRestoreCmd))); + + /* + * Copy xlog from archival storage to XLOGDIR + */ + rc = system(xlogRestoreCmd); + if (rc == 0) + { + /* + * command apparently succeeded, but let's make sure the file is + * really there now and has the correct size. + * + * XXX I made wrong-size a fatal error to ensure the DBA would notice + * it, but is that too strong? We could try to plow ahead with a + * local copy of the file ... but the problem is that there probably + * isn't one, and we'd incorrectly conclude we've reached the end of + * WAL and we're done recovering ... + */ + if (stat(xlogpath, &stat_buf) == 0) + { + if (expectedSize > 0 && stat_buf.st_size != expectedSize) + ereport(FATAL, + (errmsg("archive file \"%s\" has wrong size: %lu instead of %lu", + xlogfname, + (unsigned long) stat_buf.st_size, + (unsigned long) expectedSize))); + else + { + ereport(LOG, + (errmsg("restored log file \"%s\" from archive", + xlogfname))); + strcpy(path, xlogpath); + return true; + } + } + else + { + /* stat failed */ + if (errno != ENOENT) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not stat file \"%s\": %m", + xlogpath))); + } + } + + /* + * Remember, we rollforward UNTIL the restore fails so failure here is + * just part of the process... that makes it difficult to determine + * whether the restore failed because there isn't an archive to restore, + * or because the administrator has specified the restore program + * incorrectly. We have to assume the former. + * + * However, if the failure was due to any sort of signal, it's best to + * punt and abort recovery. (If we "return false" here, upper levels will + * assume that recovery is complete and start up the database!) It's + * essential to abort on child SIGINT and SIGQUIT, because per spec + * system() ignores SIGINT and SIGQUIT while waiting; if we see one of + * those it's a good bet we should have gotten it too. Aborting on other + * signals such as SIGTERM seems a good idea as well. + * + * Per the Single Unix Spec, shells report exit status > 128 when a called + * command died on a signal. Also, 126 and 127 are used to report + * problems such as an unfindable command; treat those as fatal errors + * too. + */ + signaled = WIFSIGNALED(rc) || WEXITSTATUS(rc) > 125; + + ereport(signaled ? FATAL : DEBUG2, + (errmsg("could not restore file \"%s\" from archive: return code %d", + xlogfname, rc))); + + /* + * if an archived file is not available, there might still be a version of + * this file in XLOGDIR, so return that as the filename to open. + * + * In many recovery scenarios we expect this to fail also, but if so that + * just means we've reached the end of WAL. + */ + snprintf(path, MAXPGPATH, XLOGDIR "/%s", xlogfname); + return false; + } + + /* + * Preallocate log files beyond the specified log endpoint. + * + * XXX this is currently extremely conservative, since it forces only one + * future log segment to exist, and even that only if we are 75% done with + * the current one. This is only appropriate for very low-WAL-volume systems. + * High-volume systems will be OK once they've built up a sufficient set of + * recycled log segments, but the startup transient is likely to include + * a lot of segment creations by foreground processes, which is not so good. + */ + static void + PreallocXlogFiles(XLogRecPtr endptr) + { + uint32 _logId; + uint32 _logSeg; + int lf; + bool use_existent; + + XLByteToPrevSeg(endptr, _logId, _logSeg); + if ((endptr.xrecoff - 1) % XLogSegSize >= + (uint32) (0.75 * XLogSegSize)) + { + NextLogSeg(_logId, _logSeg); + use_existent = true; + lf = XLogFileInit(_logId, _logSeg, &use_existent, true); + close(lf); + if (!use_existent) + CheckpointStats.ckpt_segs_added++; + } + } + + /* + * Recycle or remove all log files older or equal to passed log/seg# + * + * endptr is current (or recent) end of xlog; this is used to determine + * whether we want to recycle rather than delete no-longer-wanted log files. + */ + static void + RemoveOldXlogFiles(uint32 log, uint32 seg, XLogRecPtr endptr) + { + uint32 endlogId; + uint32 endlogSeg; + int max_advance; + DIR *xldir; + struct dirent *xlde; + char lastoff[MAXFNAMELEN]; + char path[MAXPGPATH]; + + /* + * Initialize info about where to try to recycle to. We allow recycling + * segments up to XLOGfileslop segments beyond the current XLOG location. + */ + XLByteToPrevSeg(endptr, endlogId, endlogSeg); + max_advance = XLOGfileslop; + + xldir = AllocateDir(XLOGDIR); + if (xldir == NULL) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open transaction log directory \"%s\": %m", + XLOGDIR))); + + XLogFileName(lastoff, ThisTimeLineID, log, seg); + + while ((xlde = ReadDir(xldir, XLOGDIR)) != NULL) + { + /* + * We ignore the timeline part of the XLOG segment identifiers in + * deciding whether a segment is still needed. This ensures that we + * won't prematurely remove a segment from a parent timeline. We could + * probably be a little more proactive about removing segments of + * non-parent timelines, but that would be a whole lot more + * complicated. + * + * We use the alphanumeric sorting property of the filenames to decide + * which ones are earlier than the lastoff segment. + */ + if (strlen(xlde->d_name) == 24 && + strspn(xlde->d_name, "0123456789ABCDEF") == 24 && + strcmp(xlde->d_name + 8, lastoff + 8) <= 0) + { + if (XLogArchiveCheckDone(xlde->d_name)) + { + snprintf(path, MAXPGPATH, XLOGDIR "/%s", xlde->d_name); + + /* + * Before deleting the file, see if it can be recycled as a + * future log segment. + */ + if (InstallXLogFileSegment(&endlogId, &endlogSeg, path, + true, &max_advance, + true)) + { + ereport(DEBUG2, + (errmsg("recycled transaction log file \"%s\"", + xlde->d_name))); + CheckpointStats.ckpt_segs_recycled++; + /* Needn't recheck that slot on future iterations */ + if (max_advance > 0) + { + NextLogSeg(endlogId, endlogSeg); + max_advance--; + } + } + else + { + /* No need for any more future segments... */ + ereport(DEBUG2, + (errmsg("removing transaction log file \"%s\"", + xlde->d_name))); + unlink(path); + CheckpointStats.ckpt_segs_removed++; + } + + XLogArchiveCleanup(xlde->d_name); + } + } + } + + FreeDir(xldir); + } + + /* + * Verify whether pg_xlog and pg_xlog/archive_status exist. + * If the latter does not exist, recreate it. + * + * It is not the goal of this function to verify the contents of these + * directories, but to help in cases where someone has performed a cluster + * copy for PITR purposes but omitted pg_xlog from the copy. + * + * We could also recreate pg_xlog if it doesn't exist, but a deliberate + * policy decision was made not to. It is fairly common for pg_xlog to be + * a symlink, and if that was the DBA's intent then automatically making a + * plain directory would result in degraded performance with no notice. + */ + static void + ValidateXLOGDirectoryStructure(void) + { + char path[MAXPGPATH]; + struct stat stat_buf; + + /* Check for pg_xlog; if it doesn't exist, error out */ + if (stat(XLOGDIR, &stat_buf) != 0 || + !S_ISDIR(stat_buf.st_mode)) + ereport(FATAL, + (errmsg("required WAL directory \"%s\" does not exist", + XLOGDIR))); + + /* Check for archive_status */ + snprintf(path, MAXPGPATH, XLOGDIR "/archive_status"); + if (stat(path, &stat_buf) == 0) + { + /* Check for weird cases where it exists but isn't a directory */ + if (!S_ISDIR(stat_buf.st_mode)) + ereport(FATAL, + (errmsg("required WAL directory \"%s\" does not exist", + path))); + } + else + { + ereport(LOG, + (errmsg("creating missing WAL directory \"%s\"", path))); + if (mkdir(path, 0700) < 0) + ereport(FATAL, + (errmsg("could not create missing directory \"%s\": %m", + path))); + } + } + + /* + * Remove previous backup history files. This also retries creation of + * .ready files for any backup history files for which XLogArchiveNotify + * failed earlier. + */ + static void + CleanupBackupHistory(void) + { + DIR *xldir; + struct dirent *xlde; + char path[MAXPGPATH]; + + xldir = AllocateDir(XLOGDIR); + if (xldir == NULL) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open transaction log directory \"%s\": %m", + XLOGDIR))); + + while ((xlde = ReadDir(xldir, XLOGDIR)) != NULL) + { + if (strlen(xlde->d_name) > 24 && + strspn(xlde->d_name, "0123456789ABCDEF") == 24 && + strcmp(xlde->d_name + strlen(xlde->d_name) - strlen(".backup"), + ".backup") == 0) + { + if (XLogArchiveCheckDone(xlde->d_name)) + { + ereport(DEBUG2, + (errmsg("removing transaction log backup history file \"%s\"", + xlde->d_name))); + snprintf(path, MAXPGPATH, XLOGDIR "/%s", xlde->d_name); + unlink(path); + XLogArchiveCleanup(xlde->d_name); + } + } + } + + FreeDir(xldir); + } + + /* + * Restore the backup blocks present in an XLOG record, if any. + * + * We assume all of the record has been read into memory at *record. + * + * Note: when a backup block is available in XLOG, we restore it + * unconditionally, even if the page in the database appears newer. + * This is to protect ourselves against database pages that were partially + * or incorrectly written during a crash. We assume that the XLOG data + * must be good because it has passed a CRC check, while the database + * page might not be. This will force us to replay all subsequent + * modifications of the page that appear in XLOG, rather than possibly + * ignoring them as already applied, but that's not a huge drawback. + * + * If 'cleanup' is true, a cleanup lock is used when restoring blocks. + * Otherwise, a normal exclusive lock is used. At the moment, that's just + * pro forma, because there can't be any regular backends in the system + * during recovery. The 'cleanup' argument applies to all backup blocks + * in the WAL record, that suffices for now. + */ + void + RestoreBkpBlocks(XLogRecPtr lsn, XLogRecord *record, bool cleanup) + { + Buffer buffer; + Page page; + BkpBlock bkpb; + char *blk; + int i; + + if (!(record->xl_info & XLR_BKP_BLOCK_MASK)) + return; + + blk = (char *) XLogRecGetData(record) + record->xl_len; + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + if (!(record->xl_info & XLR_SET_BKP_BLOCK(i))) + continue; + + memcpy(&bkpb, blk, sizeof(BkpBlock)); + blk += sizeof(BkpBlock); + + buffer = XLogReadBufferExtended(bkpb.node, bkpb.fork, bkpb.block, + RBM_ZERO); + Assert(BufferIsValid(buffer)); + if (cleanup) + LockBufferForCleanup(buffer); + else + LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE); + + page = (Page) BufferGetPage(buffer); + + if (bkpb.hole_length == 0) + { + memcpy((char *) page, blk, BLCKSZ); + } + else + { + /* must zero-fill the hole */ + MemSet((char *) page, 0, BLCKSZ); + memcpy((char *) page, blk, bkpb.hole_offset); + memcpy((char *) page + (bkpb.hole_offset + bkpb.hole_length), + blk + bkpb.hole_offset, + BLCKSZ - (bkpb.hole_offset + bkpb.hole_length)); + } + + PageSetLSN(page, lsn); + PageSetTLI(page, ThisTimeLineID); + MarkBufferDirty(buffer); + UnlockReleaseBuffer(buffer); + + blk += BLCKSZ - bkpb.hole_length; + } + } + + /* + * CRC-check an XLOG record. We do not believe the contents of an XLOG + * record (other than to the minimal extent of computing the amount of + * data to read in) until we've checked the CRCs. + * + * We assume all of the record has been read into memory at *record. + */ + static bool + RecordIsValid(XLogRecord *record, XLogRecPtr recptr, int emode) + { + pg_crc32 crc; + int i; + uint32 len = record->xl_len; + BkpBlock bkpb; + char *blk; + + /* First the rmgr data */ + INIT_CRC32(crc); + COMP_CRC32(crc, XLogRecGetData(record), len); + + /* Add in the backup blocks, if any */ + blk = (char *) XLogRecGetData(record) + len; + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + uint32 blen; + + if (!(record->xl_info & XLR_SET_BKP_BLOCK(i))) + continue; + + memcpy(&bkpb, blk, sizeof(BkpBlock)); + if (bkpb.hole_offset + bkpb.hole_length > BLCKSZ) + { + ereport(emode, + (errmsg("incorrect hole size in record at %X/%X", + recptr.xlogid, recptr.xrecoff))); + return false; + } + blen = sizeof(BkpBlock) + BLCKSZ - bkpb.hole_length; + COMP_CRC32(crc, blk, blen); + blk += blen; + } + + /* Check that xl_tot_len agrees with our calculation */ + if (blk != (char *) record + record->xl_tot_len) + { + ereport(emode, + (errmsg("incorrect total length in record at %X/%X", + recptr.xlogid, recptr.xrecoff))); + return false; + } + + /* Finally include the record header */ + COMP_CRC32(crc, (char *) record + sizeof(pg_crc32), + SizeOfXLogRecord - sizeof(pg_crc32)); + FIN_CRC32(crc); + + if (!EQ_CRC32(record->xl_crc, crc)) + { + ereport(emode, + (errmsg("incorrect resource manager data checksum in record at %X/%X", + recptr.xlogid, recptr.xrecoff))); + return false; + } + + return true; + } + + /* + * Attempt to read an XLOG record. + * + * If RecPtr is not NULL, try to read a record at that position. Otherwise + * try to read a record just after the last one previously read. + * + * If no valid record is available, returns NULL, or fails if emode is PANIC. + * (emode must be either PANIC or LOG.) + * + * The record is copied into readRecordBuf, so that on successful return, + * the returned record pointer always points there. + */ + static XLogRecord * + ReadRecord(XLogRecPtr *RecPtr, int emode) + { + XLogRecord *record; + char *buffer; + XLogRecPtr tmpRecPtr = EndRecPtr; + bool randAccess = false; + uint32 len, + total_len; + uint32 targetPageOff; + uint32 targetRecOff; + uint32 pageHeaderSize; + + if (readBuf == NULL) + { + /* + * First time through, permanently allocate readBuf. We do it this + * way, rather than just making a static array, for two reasons: (1) + * no need to waste the storage in most instantiations of the backend; + * (2) a static char array isn't guaranteed to have any particular + * alignment, whereas malloc() will provide MAXALIGN'd storage. + */ + readBuf = (char *) malloc(XLOG_BLCKSZ); + Assert(readBuf != NULL); + } + + if (RecPtr == NULL) + { + RecPtr = &tmpRecPtr; + /* fast case if next record is on same page */ + if (nextRecord != NULL) + { + record = nextRecord; + goto got_record; + } + /* align old recptr to next page */ + if (tmpRecPtr.xrecoff % XLOG_BLCKSZ != 0) + tmpRecPtr.xrecoff += (XLOG_BLCKSZ - tmpRecPtr.xrecoff % XLOG_BLCKSZ); + if (tmpRecPtr.xrecoff >= XLogFileSize) + { + (tmpRecPtr.xlogid)++; + tmpRecPtr.xrecoff = 0; + } + /* We will account for page header size below */ + } + else + { + if (!XRecOffIsValid(RecPtr->xrecoff)) + ereport(PANIC, + (errmsg("invalid record offset at %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + + /* + * Since we are going to a random position in WAL, forget any prior + * state about what timeline we were in, and allow it to be any + * timeline in expectedTLIs. We also set a flag to allow curFileTLI + * to go backwards (but we can't reset that variable right here, since + * we might not change files at all). + */ + lastPageTLI = 0; /* see comment in ValidXLOGHeader */ + randAccess = true; /* allow curFileTLI to go backwards too */ + } + + if (readFile >= 0 && !XLByteInSeg(*RecPtr, readId, readSeg)) + { + close(readFile); + readFile = -1; + } + XLByteToSeg(*RecPtr, readId, readSeg); + if (readFile < 0) + { + /* Now it's okay to reset curFileTLI if random fetch */ + if (randAccess) + curFileTLI = 0; + + readFile = XLogFileRead(readId, readSeg, emode); + if (readFile < 0) + goto next_record_is_invalid; + + /* + * Whenever switching to a new WAL segment, we read the first page of + * the file and validate its header, even if that's not where the + * target record is. This is so that we can check the additional + * identification info that is present in the first page's "long" + * header. + */ + readOff = 0; + if (read(readFile, readBuf, XLOG_BLCKSZ) != XLOG_BLCKSZ) + { + ereport(emode, + (errcode_for_file_access(), + errmsg("could not read from log file %u, segment %u, offset %u: %m", + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + if (!ValidXLOGHeader((XLogPageHeader) readBuf, emode)) + goto next_record_is_invalid; + } + + targetPageOff = ((RecPtr->xrecoff % XLogSegSize) / XLOG_BLCKSZ) * XLOG_BLCKSZ; + if (readOff != targetPageOff) + { + readOff = targetPageOff; + if (lseek(readFile, (off_t) readOff, SEEK_SET) < 0) + { + ereport(emode, + (errcode_for_file_access(), + errmsg("could not seek in log file %u, segment %u to offset %u: %m", + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + if (read(readFile, readBuf, XLOG_BLCKSZ) != XLOG_BLCKSZ) + { + ereport(emode, + (errcode_for_file_access(), + errmsg("could not read from log file %u, segment %u, offset %u: %m", + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + if (!ValidXLOGHeader((XLogPageHeader) readBuf, emode)) + goto next_record_is_invalid; + } + pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) readBuf); + targetRecOff = RecPtr->xrecoff % XLOG_BLCKSZ; + if (targetRecOff == 0) + { + /* + * Can only get here in the continuing-from-prev-page case, because + * XRecOffIsValid eliminated the zero-page-offset case otherwise. Need + * to skip over the new page's header. + */ + tmpRecPtr.xrecoff += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + ereport(emode, + (errmsg("invalid record offset at %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + if ((((XLogPageHeader) readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) + { + ereport(emode, + (errmsg("contrecord is requested by %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + record = (XLogRecord *) ((char *) readBuf + RecPtr->xrecoff % XLOG_BLCKSZ); + + got_record:; + + /* + * xl_len == 0 is bad data for everything except XLOG SWITCH, where it is + * required. + */ + if (record->xl_rmid == RM_XLOG_ID && record->xl_info == XLOG_SWITCH) + { + if (record->xl_len != 0) + { + ereport(emode, + (errmsg("invalid xlog switch record at %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + } + else if (record->xl_len == 0) + { + ereport(emode, + (errmsg("record with zero length at %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + if (record->xl_tot_len < SizeOfXLogRecord + record->xl_len || + record->xl_tot_len > SizeOfXLogRecord + record->xl_len + + XLR_MAX_BKP_BLOCKS * (sizeof(BkpBlock) + BLCKSZ)) + { + ereport(emode, + (errmsg("invalid record length at %X/%X", + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + if (record->xl_rmid > RM_MAX_ID) + { + ereport(emode, + (errmsg("invalid resource manager ID %u at %X/%X", + record->xl_rmid, RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + if (randAccess) + { + /* + * We can't exactly verify the prev-link, but surely it should be less + * than the record's own address. + */ + if (!XLByteLT(record->xl_prev, *RecPtr)) + { + ereport(emode, + (errmsg("record with incorrect prev-link %X/%X at %X/%X", + record->xl_prev.xlogid, record->xl_prev.xrecoff, + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + } + else + { + /* + * Record's prev-link should exactly match our previous location. This + * check guards against torn WAL pages where a stale but valid-looking + * WAL record starts on a sector boundary. + */ + if (!XLByteEQ(record->xl_prev, ReadRecPtr)) + { + ereport(emode, + (errmsg("record with incorrect prev-link %X/%X at %X/%X", + record->xl_prev.xlogid, record->xl_prev.xrecoff, + RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + } + + /* + * Allocate or enlarge readRecordBuf as needed. To avoid useless small + * increases, round its size to a multiple of XLOG_BLCKSZ, and make sure + * it's at least 4*Max(BLCKSZ, XLOG_BLCKSZ) to start with. (That is + * enough for all "normal" records, but very large commit or abort records + * might need more space.) + */ + total_len = record->xl_tot_len; + if (total_len > readRecordBufSize) + { + uint32 newSize = total_len; + + newSize += XLOG_BLCKSZ - (newSize % XLOG_BLCKSZ); + newSize = Max(newSize, 4 * Max(BLCKSZ, XLOG_BLCKSZ)); + if (readRecordBuf) + free(readRecordBuf); + readRecordBuf = (char *) malloc(newSize); + if (!readRecordBuf) + { + readRecordBufSize = 0; + /* We treat this as a "bogus data" condition */ + ereport(emode, + (errmsg("record length %u at %X/%X too long", + total_len, RecPtr->xlogid, RecPtr->xrecoff))); + goto next_record_is_invalid; + } + readRecordBufSize = newSize; + } + + buffer = readRecordBuf; + nextRecord = NULL; + len = XLOG_BLCKSZ - RecPtr->xrecoff % XLOG_BLCKSZ; + if (total_len > len) + { + /* Need to reassemble record */ + XLogContRecord *contrecord; + uint32 gotlen = len; + + memcpy(buffer, record, len); + record = (XLogRecord *) buffer; + buffer += len; + for (;;) + { + readOff += XLOG_BLCKSZ; + if (readOff >= XLogSegSize) + { + close(readFile); + readFile = -1; + NextLogSeg(readId, readSeg); + readFile = XLogFileRead(readId, readSeg, emode); + if (readFile < 0) + goto next_record_is_invalid; + readOff = 0; + } + if (read(readFile, readBuf, XLOG_BLCKSZ) != XLOG_BLCKSZ) + { + ereport(emode, + (errcode_for_file_access(), + errmsg("could not read from log file %u, segment %u, offset %u: %m", + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + if (!ValidXLOGHeader((XLogPageHeader) readBuf, emode)) + goto next_record_is_invalid; + if (!(((XLogPageHeader) readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + ereport(emode, + (errmsg("there is no contrecord flag in log file %u, segment %u, offset %u", + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) readBuf); + contrecord = (XLogContRecord *) ((char *) readBuf + pageHeaderSize); + if (contrecord->xl_rem_len == 0 || + total_len != (contrecord->xl_rem_len + gotlen)) + { + ereport(emode, + (errmsg("invalid contrecord length %u in log file %u, segment %u, offset %u", + contrecord->xl_rem_len, + readId, readSeg, readOff))); + goto next_record_is_invalid; + } + len = XLOG_BLCKSZ - pageHeaderSize - SizeOfXLogContRecord; + if (contrecord->xl_rem_len > len) + { + memcpy(buffer, (char *) contrecord + SizeOfXLogContRecord, len); + gotlen += len; + buffer += len; + continue; + } + memcpy(buffer, (char *) contrecord + SizeOfXLogContRecord, + contrecord->xl_rem_len); + break; + } + if (!RecordIsValid(record, *RecPtr, emode)) + goto next_record_is_invalid; + pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) readBuf); + if (XLOG_BLCKSZ - SizeOfXLogRecord >= pageHeaderSize + + MAXALIGN(SizeOfXLogContRecord + contrecord->xl_rem_len)) + { + nextRecord = (XLogRecord *) ((char *) contrecord + + MAXALIGN(SizeOfXLogContRecord + contrecord->xl_rem_len)); + } + EndRecPtr.xlogid = readId; + EndRecPtr.xrecoff = readSeg * XLogSegSize + readOff + + pageHeaderSize + + MAXALIGN(SizeOfXLogContRecord + contrecord->xl_rem_len); + ReadRecPtr = *RecPtr; + /* needn't worry about XLOG SWITCH, it can't cross page boundaries */ + return record; + } + + /* Record does not cross a page boundary */ + if (!RecordIsValid(record, *RecPtr, emode)) + goto next_record_is_invalid; + if (XLOG_BLCKSZ - SizeOfXLogRecord >= RecPtr->xrecoff % XLOG_BLCKSZ + + MAXALIGN(total_len)) + nextRecord = (XLogRecord *) ((char *) record + MAXALIGN(total_len)); + EndRecPtr.xlogid = RecPtr->xlogid; + EndRecPtr.xrecoff = RecPtr->xrecoff + MAXALIGN(total_len); + ReadRecPtr = *RecPtr; + memcpy(buffer, record, total_len); + + /* + * Special processing if it's an XLOG SWITCH record + */ + if (record->xl_rmid == RM_XLOG_ID && record->xl_info == XLOG_SWITCH) + { + /* Pretend it extends to end of segment */ + EndRecPtr.xrecoff += XLogSegSize - 1; + EndRecPtr.xrecoff -= EndRecPtr.xrecoff % XLogSegSize; + nextRecord = NULL; /* definitely not on same page */ + + /* + * Pretend that readBuf contains the last page of the segment. This is + * just to avoid Assert failure in StartupXLOG if XLOG ends with this + * segment. + */ + readOff = XLogSegSize - XLOG_BLCKSZ; + } + return (XLogRecord *) buffer; + + next_record_is_invalid:; + /* + * Reached to unused area of current WAL segment file, redo all of WAL + * records in the queue. + */ + ereport(DEBUG1, (errmsg("next record is invalid(maybe unused area)"))); + RedoRecords(); + + if (readFile >= 0) + { + close(readFile); + readFile = -1; + } + nextRecord = NULL; + return NULL; + } + + /* + * Check whether the xlog header of a page just read in looks valid. + * + * This is just a convenience subroutine to avoid duplicated code in + * ReadRecord. It's not intended for use from anywhere else. + */ + static bool + ValidXLOGHeader(XLogPageHeader hdr, int emode) + { + XLogRecPtr recaddr; + + if (hdr->xlp_magic != XLOG_PAGE_MAGIC) + { + ereport(emode, + (errmsg("invalid magic number %04X in log file %u, segment %u, offset %u", + hdr->xlp_magic, readId, readSeg, readOff))); + return false; + } + if ((hdr->xlp_info & ~XLP_ALL_FLAGS) != 0) + { + ereport(emode, + (errmsg("invalid info bits %04X in log file %u, segment %u, offset %u", + hdr->xlp_info, readId, readSeg, readOff))); + return false; + } + if (hdr->xlp_info & XLP_LONG_HEADER) + { + XLogLongPageHeader longhdr = (XLogLongPageHeader) hdr; + + if (longhdr->xlp_sysid != ControlFile->system_identifier) + { + char fhdrident_str[32]; + char sysident_str[32]; + + /* + * Format sysids separately to keep platform-dependent format code + * out of the translatable message string. + */ + snprintf(fhdrident_str, sizeof(fhdrident_str), UINT64_FORMAT, + longhdr->xlp_sysid); + snprintf(sysident_str, sizeof(sysident_str), UINT64_FORMAT, + ControlFile->system_identifier); + ereport(emode, + (errmsg("WAL file is from different system"), + errdetail("WAL file SYSID is %s, pg_control SYSID is %s", + fhdrident_str, sysident_str))); + return false; + } + if (longhdr->xlp_seg_size != XLogSegSize) + { + ereport(emode, + (errmsg("WAL file is from different system"), + errdetail("Incorrect XLOG_SEG_SIZE in page header."))); + return false; + } + if (longhdr->xlp_xlog_blcksz != XLOG_BLCKSZ) + { + ereport(emode, + (errmsg("WAL file is from different system"), + errdetail("Incorrect XLOG_BLCKSZ in page header."))); + return false; + } + } + else if (readOff == 0) + { + /* hmm, first page of file doesn't have a long header? */ + ereport(emode, + (errmsg("invalid info bits %04X in log file %u, segment %u, offset %u", + hdr->xlp_info, readId, readSeg, readOff))); + return false; + } + + recaddr.xlogid = readId; + recaddr.xrecoff = readSeg * XLogSegSize + readOff; + if (!XLByteEQ(hdr->xlp_pageaddr, recaddr)) + { + ereport(emode, + (errmsg("unexpected pageaddr %X/%X in log file %u, segment %u, offset %u", + hdr->xlp_pageaddr.xlogid, hdr->xlp_pageaddr.xrecoff, + readId, readSeg, readOff))); + return false; + } + + /* + * Check page TLI is one of the expected values. + */ + if (!list_member_int(expectedTLIs, (int) hdr->xlp_tli)) + { + ereport(emode, + (errmsg("unexpected timeline ID %u in log file %u, segment %u, offset %u", + hdr->xlp_tli, + readId, readSeg, readOff))); + return false; + } + + /* + * Since child timelines are always assigned a TLI greater than their + * immediate parent's TLI, we should never see TLI go backwards across + * successive pages of a consistent WAL sequence. + * + * Of course this check should only be applied when advancing sequentially + * across pages; therefore ReadRecord resets lastPageTLI to zero when + * going to a random page. + */ + if (hdr->xlp_tli < lastPageTLI) + { + ereport(emode, + (errmsg("out-of-sequence timeline ID %u (after %u) in log file %u, segment %u, offset %u", + hdr->xlp_tli, lastPageTLI, + readId, readSeg, readOff))); + return false; + } + lastPageTLI = hdr->xlp_tli; + return true; + } + + /* + * Try to read a timeline's history file. + * + * If successful, return the list of component TLIs (the given TLI followed by + * its ancestor TLIs). If we can't find the history file, assume that the + * timeline has no parents, and return a list of just the specified timeline + * ID. + */ + static List * + readTimeLineHistory(TimeLineID targetTLI) + { + List *result; + char path[MAXPGPATH]; + char histfname[MAXFNAMELEN]; + char fline[MAXPGPATH]; + FILE *fd; + + if (InArchiveRecovery) + { + TLHistoryFileName(histfname, targetTLI); + RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0); + } + else + TLHistoryFilePath(path, targetTLI); + + fd = AllocateFile(path, "r"); + if (fd == NULL) + { + if (errno != ENOENT) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not open file \"%s\": %m", path))); + /* Not there, so assume no parents */ + return list_make1_int((int) targetTLI); + } + + result = NIL; + + /* + * Parse the file... + */ + while (fgets(fline, sizeof(fline), fd) != NULL) + { + /* skip leading whitespace and check for # comment */ + char *ptr; + char *endptr; + TimeLineID tli; + + for (ptr = fline; *ptr; ptr++) + { + if (!isspace((unsigned char) *ptr)) + break; + } + if (*ptr == '\0' || *ptr == '#') + continue; + + /* expect a numeric timeline ID as first field of line */ + tli = (TimeLineID) strtoul(ptr, &endptr, 0); + if (endptr == ptr) + ereport(FATAL, + (errmsg("syntax error in history file: %s", fline), + errhint("Expected a numeric timeline ID."))); + + if (result && + tli <= (TimeLineID) linitial_int(result)) + ereport(FATAL, + (errmsg("invalid data in history file: %s", fline), + errhint("Timeline IDs must be in increasing sequence."))); + + /* Build list with newest item first */ + result = lcons_int((int) tli, result); + + /* we ignore the remainder of each line */ + } + + FreeFile(fd); + + if (result && + targetTLI <= (TimeLineID) linitial_int(result)) + ereport(FATAL, + (errmsg("invalid data in history file \"%s\"", path), + errhint("Timeline IDs must be less than child timeline's ID."))); + + result = lcons_int((int) targetTLI, result); + + ereport(DEBUG3, + (errmsg_internal("history of timeline %u is %s", + targetTLI, nodeToString(result)))); + + return result; + } + + /* + * Probe whether a timeline history file exists for the given timeline ID + */ + static bool + existsTimeLineHistory(TimeLineID probeTLI) + { + char path[MAXPGPATH]; + char histfname[MAXFNAMELEN]; + FILE *fd; + + if (InArchiveRecovery) + { + TLHistoryFileName(histfname, probeTLI); + RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0); + } + else + TLHistoryFilePath(path, probeTLI); + + fd = AllocateFile(path, "r"); + if (fd != NULL) + { + FreeFile(fd); + return true; + } + else + { + if (errno != ENOENT) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not open file \"%s\": %m", path))); + return false; + } + } + + /* + * Find the newest existing timeline, assuming that startTLI exists. + * + * Note: while this is somewhat heuristic, it does positively guarantee + * that (result + 1) is not a known timeline, and therefore it should + * be safe to assign that ID to a new timeline. + */ + static TimeLineID + findNewestTimeLine(TimeLineID startTLI) + { + TimeLineID newestTLI; + TimeLineID probeTLI; + + /* + * The algorithm is just to probe for the existence of timeline history + * files. XXX is it useful to allow gaps in the sequence? + */ + newestTLI = startTLI; + + for (probeTLI = startTLI + 1;; probeTLI++) + { + if (existsTimeLineHistory(probeTLI)) + { + newestTLI = probeTLI; /* probeTLI exists */ + } + else + { + /* doesn't exist, assume we're done */ + break; + } + } + + return newestTLI; + } + + /* + * Create a new timeline history file. + * + * newTLI: ID of the new timeline + * parentTLI: ID of its immediate parent + * endTLI et al: ID of the last used WAL file, for annotation purposes + * + * Currently this is only used during recovery, and so there are no locking + * considerations. But we should be just as tense as XLogFileInit to avoid + * emplacing a bogus file. + */ + static void + writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI, + TimeLineID endTLI, uint32 endLogId, uint32 endLogSeg) + { + char path[MAXPGPATH]; + char tmppath[MAXPGPATH]; + char histfname[MAXFNAMELEN]; + char xlogfname[MAXFNAMELEN]; + char buffer[BLCKSZ]; + int srcfd; + int fd; + int nbytes; + + Assert(newTLI > parentTLI); /* else bad selection of newTLI */ + + /* + * Write into a temp file name. + */ + snprintf(tmppath, MAXPGPATH, XLOGDIR "/xlogtemp.%d", (int) getpid()); + + unlink(tmppath); + + /* do not use get_sync_bit() here --- want to fsync only at end of fill */ + fd = BasicOpenFile(tmppath, O_RDWR | O_CREAT | O_EXCL, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not create file \"%s\": %m", tmppath))); + + /* + * If a history file exists for the parent, copy it verbatim + */ + if (InArchiveRecovery) + { + TLHistoryFileName(histfname, parentTLI); + RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0); + } + else + TLHistoryFilePath(path, parentTLI); + + srcfd = BasicOpenFile(path, O_RDONLY, 0); + if (srcfd < 0) + { + if (errno != ENOENT) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not open file \"%s\": %m", path))); + /* Not there, so assume parent has no parents */ + } + else + { + for (;;) + { + errno = 0; + nbytes = (int) read(srcfd, buffer, sizeof(buffer)); + if (nbytes < 0 || errno != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", path))); + if (nbytes == 0) + break; + errno = 0; + if ((int) write(fd, buffer, nbytes) != nbytes) + { + int save_errno = errno; + + /* + * If we fail to make the file, delete it to release disk + * space + */ + unlink(tmppath); + + /* + * if write didn't set errno, assume problem is no disk space + */ + errno = save_errno ? save_errno : ENOSPC; + + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write to file \"%s\": %m", tmppath))); + } + } + close(srcfd); + } + + /* + * Append one line with the details of this timeline split. + * + * If we did have a parent file, insert an extra newline just in case the + * parent file failed to end with one. + */ + XLogFileName(xlogfname, endTLI, endLogId, endLogSeg); + + snprintf(buffer, sizeof(buffer), + "%s%u\t%s\t%s transaction %u at %s\n", + (srcfd < 0) ? "" : "\n", + parentTLI, + xlogfname, + recoveryStopAfter ? "after" : "before", + recoveryStopXid, + timestamptz_to_str(recoveryStopTime)); + + nbytes = strlen(buffer); + errno = 0; + if ((int) write(fd, buffer, nbytes) != nbytes) + { + int save_errno = errno; + + /* + * If we fail to make the file, delete it to release disk space + */ + unlink(tmppath); + /* if write didn't set errno, assume problem is no disk space */ + errno = save_errno ? save_errno : ENOSPC; + + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write to file \"%s\": %m", tmppath))); + } + + if (pg_fsync(fd) != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not fsync file \"%s\": %m", tmppath))); + + if (close(fd)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not close file \"%s\": %m", tmppath))); + + + /* + * Now move the completed history file into place with its final name. + */ + TLHistoryFilePath(path, newTLI); + + /* + * Prefer link() to rename() here just to be really sure that we don't + * overwrite an existing logfile. However, there shouldn't be one, so + * rename() is an acceptable substitute except for the truly paranoid. + */ + #if HAVE_WORKING_LINK + if (link(tmppath, path) < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not link file \"%s\" to \"%s\": %m", + tmppath, path))); + unlink(tmppath); + #else + if (rename(tmppath, path) < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\": %m", + tmppath, path))); + #endif + + /* The history file can be archived immediately. */ + TLHistoryFileName(histfname, newTLI); + XLogArchiveNotify(histfname); + } + + /* + * I/O routines for pg_control + * + * *ControlFile is a buffer in shared memory that holds an image of the + * contents of pg_control. WriteControlFile() initializes pg_control + * given a preloaded buffer, ReadControlFile() loads the buffer from + * the pg_control file (during postmaster or standalone-backend startup), + * and UpdateControlFile() rewrites pg_control after we modify xlog state. + * + * For simplicity, WriteControlFile() initializes the fields of pg_control + * that are related to checking backend/database compatibility, and + * ReadControlFile() verifies they are correct. We could split out the + * I/O and compatibility-check functions, but there seems no need currently. + */ + static void + WriteControlFile(void) + { + int fd; + char buffer[PG_CONTROL_SIZE]; /* need not be aligned */ + + /* + * Initialize version and compatibility-check fields + */ + ControlFile->pg_control_version = PG_CONTROL_VERSION; + ControlFile->catalog_version_no = CATALOG_VERSION_NO; + + ControlFile->maxAlign = MAXIMUM_ALIGNOF; + ControlFile->floatFormat = FLOATFORMAT_VALUE; + + ControlFile->blcksz = BLCKSZ; + ControlFile->relseg_size = RELSEG_SIZE; + ControlFile->xlog_blcksz = XLOG_BLCKSZ; + ControlFile->xlog_seg_size = XLOG_SEG_SIZE; + + ControlFile->nameDataLen = NAMEDATALEN; + ControlFile->indexMaxKeys = INDEX_MAX_KEYS; + + ControlFile->toast_max_chunk_size = TOAST_MAX_CHUNK_SIZE; + + #ifdef HAVE_INT64_TIMESTAMP + ControlFile->enableIntTimes = true; + #else + ControlFile->enableIntTimes = false; + #endif + ControlFile->float4ByVal = FLOAT4PASSBYVAL; + ControlFile->float8ByVal = FLOAT8PASSBYVAL; + + /* Contents are protected with a CRC */ + INIT_CRC32(ControlFile->crc); + COMP_CRC32(ControlFile->crc, + (char *) ControlFile, + offsetof(ControlFileData, crc)); + FIN_CRC32(ControlFile->crc); + + /* + * We write out PG_CONTROL_SIZE bytes into pg_control, zero-padding the + * excess over sizeof(ControlFileData). This reduces the odds of + * premature-EOF errors when reading pg_control. We'll still fail when we + * check the contents of the file, but hopefully with a more specific + * error than "couldn't read pg_control". + */ + if (sizeof(ControlFileData) > PG_CONTROL_SIZE) + elog(PANIC, "sizeof(ControlFileData) is larger than PG_CONTROL_SIZE; fix either one"); + + memset(buffer, 0, PG_CONTROL_SIZE); + memcpy(buffer, ControlFile, sizeof(ControlFileData)); + + fd = BasicOpenFile(XLOG_CONTROL_FILE, + O_RDWR | O_CREAT | O_EXCL | PG_BINARY, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not create control file \"%s\": %m", + XLOG_CONTROL_FILE))); + + errno = 0; + if (write(fd, buffer, PG_CONTROL_SIZE) != PG_CONTROL_SIZE) + { + /* if write didn't set errno, assume problem is no disk space */ + if (errno == 0) + errno = ENOSPC; + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not write to control file: %m"))); + } + + if (pg_fsync(fd) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync control file: %m"))); + + if (close(fd)) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not close control file: %m"))); + } + + static void + ReadControlFile(void) + { + pg_crc32 crc; + int fd; + + /* + * Read data... + */ + fd = BasicOpenFile(XLOG_CONTROL_FILE, + O_RDWR | PG_BINARY, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not open control file \"%s\": %m", + XLOG_CONTROL_FILE))); + + if (read(fd, ControlFile, sizeof(ControlFileData)) != sizeof(ControlFileData)) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not read from control file: %m"))); + + close(fd); + + /* + * Check for expected pg_control format version. If this is wrong, the + * CRC check will likely fail because we'll be checking the wrong number + * of bytes. Complaining about wrong version will probably be more + * enlightening than complaining about wrong CRC. + */ + + if (ControlFile->pg_control_version != PG_CONTROL_VERSION && ControlFile->pg_control_version % 65536 == 0 && ControlFile->pg_control_version / 65536 != 0) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with PG_CONTROL_VERSION %d (0x%08x)," + " but the server was compiled with PG_CONTROL_VERSION %d (0x%08x).", + ControlFile->pg_control_version, ControlFile->pg_control_version, + PG_CONTROL_VERSION, PG_CONTROL_VERSION), + errhint("This could be a problem of mismatched byte ordering. It looks like you need to initdb."))); + + if (ControlFile->pg_control_version != PG_CONTROL_VERSION) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with PG_CONTROL_VERSION %d," + " but the server was compiled with PG_CONTROL_VERSION %d.", + ControlFile->pg_control_version, PG_CONTROL_VERSION), + errhint("It looks like you need to initdb."))); + + /* Now check the CRC. */ + INIT_CRC32(crc); + COMP_CRC32(crc, + (char *) ControlFile, + offsetof(ControlFileData, crc)); + FIN_CRC32(crc); + + if (!EQ_CRC32(crc, ControlFile->crc)) + ereport(FATAL, + (errmsg("incorrect checksum in control file"))); + + /* + * Do compatibility checking immediately. We do this here for 2 reasons: + * + * (1) if the database isn't compatible with the backend executable, we + * want to abort before we can possibly do any damage; + * + * (2) this code is executed in the postmaster, so the setlocale() will + * propagate to forked backends, which aren't going to read this file for + * themselves. (These locale settings are considered critical + * compatibility items because they can affect sort order of indexes.) + */ + if (ControlFile->catalog_version_no != CATALOG_VERSION_NO) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with CATALOG_VERSION_NO %d," + " but the server was compiled with CATALOG_VERSION_NO %d.", + ControlFile->catalog_version_no, CATALOG_VERSION_NO), + errhint("It looks like you need to initdb."))); + if (ControlFile->maxAlign != MAXIMUM_ALIGNOF) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with MAXALIGN %d," + " but the server was compiled with MAXALIGN %d.", + ControlFile->maxAlign, MAXIMUM_ALIGNOF), + errhint("It looks like you need to initdb."))); + if (ControlFile->floatFormat != FLOATFORMAT_VALUE) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster appears to use a different floating-point number format than the server executable."), + errhint("It looks like you need to initdb."))); + if (ControlFile->blcksz != BLCKSZ) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with BLCKSZ %d," + " but the server was compiled with BLCKSZ %d.", + ControlFile->blcksz, BLCKSZ), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->relseg_size != RELSEG_SIZE) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with RELSEG_SIZE %d," + " but the server was compiled with RELSEG_SIZE %d.", + ControlFile->relseg_size, RELSEG_SIZE), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->xlog_blcksz != XLOG_BLCKSZ) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with XLOG_BLCKSZ %d," + " but the server was compiled with XLOG_BLCKSZ %d.", + ControlFile->xlog_blcksz, XLOG_BLCKSZ), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->xlog_seg_size != XLOG_SEG_SIZE) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with XLOG_SEG_SIZE %d," + " but the server was compiled with XLOG_SEG_SIZE %d.", + ControlFile->xlog_seg_size, XLOG_SEG_SIZE), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->nameDataLen != NAMEDATALEN) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with NAMEDATALEN %d," + " but the server was compiled with NAMEDATALEN %d.", + ControlFile->nameDataLen, NAMEDATALEN), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->indexMaxKeys != INDEX_MAX_KEYS) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with INDEX_MAX_KEYS %d," + " but the server was compiled with INDEX_MAX_KEYS %d.", + ControlFile->indexMaxKeys, INDEX_MAX_KEYS), + errhint("It looks like you need to recompile or initdb."))); + if (ControlFile->toast_max_chunk_size != TOAST_MAX_CHUNK_SIZE) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with TOAST_MAX_CHUNK_SIZE %d," + " but the server was compiled with TOAST_MAX_CHUNK_SIZE %d.", + ControlFile->toast_max_chunk_size, (int) TOAST_MAX_CHUNK_SIZE), + errhint("It looks like you need to recompile or initdb."))); + + #ifdef HAVE_INT64_TIMESTAMP + if (ControlFile->enableIntTimes != true) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized without HAVE_INT64_TIMESTAMP" + " but the server was compiled with HAVE_INT64_TIMESTAMP."), + errhint("It looks like you need to recompile or initdb."))); + #else + if (ControlFile->enableIntTimes != false) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with HAVE_INT64_TIMESTAMP" + " but the server was compiled without HAVE_INT64_TIMESTAMP."), + errhint("It looks like you need to recompile or initdb."))); + #endif + + #ifdef USE_FLOAT4_BYVAL + if (ControlFile->float4ByVal != true) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized without USE_FLOAT4_BYVAL" + " but the server was compiled with USE_FLOAT4_BYVAL."), + errhint("It looks like you need to recompile or initdb."))); + #else + if (ControlFile->float4ByVal != false) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with USE_FLOAT4_BYVAL" + " but the server was compiled without USE_FLOAT4_BYVAL."), + errhint("It looks like you need to recompile or initdb."))); + #endif + + #ifdef USE_FLOAT8_BYVAL + if (ControlFile->float8ByVal != true) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized without USE_FLOAT8_BYVAL" + " but the server was compiled with USE_FLOAT8_BYVAL."), + errhint("It looks like you need to recompile or initdb."))); + #else + if (ControlFile->float8ByVal != false) + ereport(FATAL, + (errmsg("database files are incompatible with server"), + errdetail("The database cluster was initialized with USE_FLOAT8_BYVAL" + " but the server was compiled without USE_FLOAT8_BYVAL."), + errhint("It looks like you need to recompile or initdb."))); + #endif + } + + void + UpdateControlFile(void) + { + int fd; + + INIT_CRC32(ControlFile->crc); + COMP_CRC32(ControlFile->crc, + (char *) ControlFile, + offsetof(ControlFileData, crc)); + FIN_CRC32(ControlFile->crc); + + fd = BasicOpenFile(XLOG_CONTROL_FILE, + O_RDWR | PG_BINARY, + S_IRUSR | S_IWUSR); + if (fd < 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not open control file \"%s\": %m", + XLOG_CONTROL_FILE))); + + errno = 0; + if (write(fd, ControlFile, sizeof(ControlFileData)) != sizeof(ControlFileData)) + { + /* if write didn't set errno, assume problem is no disk space */ + if (errno == 0) + errno = ENOSPC; + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not write to control file: %m"))); + } + + if (pg_fsync(fd) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync control file: %m"))); + + if (close(fd)) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not close control file: %m"))); + } + + /* + * Initialization of shared memory for XLOG + */ + Size + XLOGShmemSize(void) + { + Size size; + + /* XLogCtl */ + size = sizeof(XLogCtlData); + /* xlblocks array */ + size = add_size(size, mul_size(sizeof(XLogRecPtr), XLOGbuffers)); + /* extra alignment padding for XLOG I/O buffers */ + size = add_size(size, ALIGNOF_XLOG_BUFFER); + /* and the buffers themselves */ + size = add_size(size, mul_size(XLOG_BLCKSZ, XLOGbuffers)); + + /* + * Note: we don't count ControlFileData, it comes out of the "slop factor" + * added by CreateSharedMemoryAndSemaphores. This lets us use this + * routine again below to compute the actual allocation size. + */ + + return size; + } + + void + XLOGShmemInit(void) + { + bool foundCFile, + foundXLog; + char *allocptr; + + ControlFile = (ControlFileData *) + ShmemInitStruct("Control File", sizeof(ControlFileData), &foundCFile); + XLogCtl = (XLogCtlData *) + ShmemInitStruct("XLOG Ctl", XLOGShmemSize(), &foundXLog); + + if (foundCFile || foundXLog) + { + /* both should be present or neither */ + Assert(foundCFile && foundXLog); + return; + } + + memset(XLogCtl, 0, sizeof(XLogCtlData)); + + /* + * Since XLogCtlData contains XLogRecPtr fields, its sizeof should be a + * multiple of the alignment for same, so no extra alignment padding is + * needed here. + */ + allocptr = ((char *) XLogCtl) + sizeof(XLogCtlData); + XLogCtl->xlblocks = (XLogRecPtr *) allocptr; + memset(XLogCtl->xlblocks, 0, sizeof(XLogRecPtr) * XLOGbuffers); + allocptr += sizeof(XLogRecPtr) * XLOGbuffers; + + /* + * Align the start of the page buffers to an ALIGNOF_XLOG_BUFFER boundary. + */ + allocptr = (char *) TYPEALIGN(ALIGNOF_XLOG_BUFFER, allocptr); + XLogCtl->pages = allocptr; + memset(XLogCtl->pages, 0, (Size) XLOG_BLCKSZ * XLOGbuffers); + + /* + * Do basic initialization of XLogCtl shared data. (StartupXLOG will fill + * in additional info.) + */ + XLogCtl->XLogCacheBlck = XLOGbuffers - 1; + XLogCtl->Insert.currpage = (XLogPageHeader) (XLogCtl->pages); + SpinLockInit(&XLogCtl->info_lck); + + /* + * If we are not in bootstrap mode, pg_control should already exist. Read + * and validate it immediately (see comments in ReadControlFile() for the + * reasons why). + */ + if (!IsBootstrapProcessingMode()) + ReadControlFile(); + } + + /* + * This func must be called ONCE on system install. It creates pg_control + * and the initial XLOG segment. + */ + void + BootStrapXLOG(void) + { + CheckPoint checkPoint; + char *buffer; + XLogPageHeader page; + XLogLongPageHeader longpage; + XLogRecord *record; + bool use_existent; + uint64 sysidentifier; + struct timeval tv; + pg_crc32 crc; + + /* + * Select a hopefully-unique system identifier code for this installation. + * We use the result of gettimeofday(), including the fractional seconds + * field, as being about as unique as we can easily get. (Think not to + * use random(), since it hasn't been seeded and there's no portable way + * to seed it other than the system clock value...) The upper half of the + * uint64 value is just the tv_sec part, while the lower half is the XOR + * of tv_sec and tv_usec. This is to ensure that we don't lose uniqueness + * unnecessarily if "uint64" is really only 32 bits wide. A person + * knowing this encoding can determine the initialization time of the + * installation, which could perhaps be useful sometimes. + */ + gettimeofday(&tv, NULL); + sysidentifier = ((uint64) tv.tv_sec) << 32; + sysidentifier |= (uint32) (tv.tv_sec | tv.tv_usec); + + /* First timeline ID is always 1 */ + ThisTimeLineID = 1; + + /* page buffer must be aligned suitably for O_DIRECT */ + buffer = (char *) palloc(XLOG_BLCKSZ + ALIGNOF_XLOG_BUFFER); + page = (XLogPageHeader) TYPEALIGN(ALIGNOF_XLOG_BUFFER, buffer); + memset(page, 0, XLOG_BLCKSZ); + + /* Set up information for the initial checkpoint record */ + checkPoint.redo.xlogid = 0; + checkPoint.redo.xrecoff = SizeOfXLogLongPHD; + checkPoint.ThisTimeLineID = ThisTimeLineID; + checkPoint.nextXidEpoch = 0; + checkPoint.nextXid = FirstNormalTransactionId; + checkPoint.nextOid = FirstBootstrapObjectId; + checkPoint.nextMulti = FirstMultiXactId; + checkPoint.nextMultiOffset = 0; + checkPoint.time = (pg_time_t) time(NULL); + + ShmemVariableCache->nextXid = checkPoint.nextXid; + ShmemVariableCache->nextOid = checkPoint.nextOid; + ShmemVariableCache->oidCount = 0; + MultiXactSetNextMXact(checkPoint.nextMulti, checkPoint.nextMultiOffset); + + /* Set up the XLOG page header */ + page->xlp_magic = XLOG_PAGE_MAGIC; + page->xlp_info = XLP_LONG_HEADER; + page->xlp_tli = ThisTimeLineID; + page->xlp_pageaddr.xlogid = 0; + page->xlp_pageaddr.xrecoff = 0; + longpage = (XLogLongPageHeader) page; + longpage->xlp_sysid = sysidentifier; + longpage->xlp_seg_size = XLogSegSize; + longpage->xlp_xlog_blcksz = XLOG_BLCKSZ; + + /* Insert the initial checkpoint record */ + record = (XLogRecord *) ((char *) page + SizeOfXLogLongPHD); + record->xl_prev.xlogid = 0; + record->xl_prev.xrecoff = 0; + record->xl_xid = InvalidTransactionId; + record->xl_tot_len = SizeOfXLogRecord + sizeof(checkPoint); + record->xl_len = sizeof(checkPoint); + record->xl_info = XLOG_CHECKPOINT_SHUTDOWN; + record->xl_rmid = RM_XLOG_ID; + memcpy(XLogRecGetData(record), &checkPoint, sizeof(checkPoint)); + + INIT_CRC32(crc); + COMP_CRC32(crc, &checkPoint, sizeof(checkPoint)); + COMP_CRC32(crc, (char *) record + sizeof(pg_crc32), + SizeOfXLogRecord - sizeof(pg_crc32)); + FIN_CRC32(crc); + record->xl_crc = crc; + + /* Create first XLOG segment file */ + use_existent = false; + openLogFile = XLogFileInit(0, 0, &use_existent, false); + + /* Write the first page with the initial record */ + errno = 0; + if (write(openLogFile, page, XLOG_BLCKSZ) != XLOG_BLCKSZ) + { + /* if write didn't set errno, assume problem is no disk space */ + if (errno == 0) + errno = ENOSPC; + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not write bootstrap transaction log file: %m"))); + } + + if (pg_fsync(openLogFile) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync bootstrap transaction log file: %m"))); + + if (close(openLogFile)) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not close bootstrap transaction log file: %m"))); + + openLogFile = -1; + + /* Now create pg_control */ + + memset(ControlFile, 0, sizeof(ControlFileData)); + /* Initialize pg_control status fields */ + ControlFile->system_identifier = sysidentifier; + ControlFile->state = DB_SHUTDOWNED; + ControlFile->time = checkPoint.time; + ControlFile->checkPoint = checkPoint.redo; + ControlFile->checkPointCopy = checkPoint; + /* some additional ControlFile fields are set in WriteControlFile() */ + + WriteControlFile(); + + /* Bootstrap the commit log, too */ + BootStrapCLOG(); + BootStrapSUBTRANS(); + BootStrapMultiXact(); + + pfree(buffer); + } + + static char * + str_time(pg_time_t tnow) + { + static char buf[128]; + + pg_strftime(buf, sizeof(buf), + "%Y-%m-%d %H:%M:%S %Z", + pg_localtime(&tnow, log_timezone)); + + return buf; + } + + /* + * See if there is a recovery command file (recovery.conf), and if so + * read in parameters for archive recovery. + * + * XXX longer term intention is to expand this to + * cater for additional parameters and controls + * possibly use a flex lexer similar to the GUC one + */ + static void + readRecoveryCommandFile(void) + { + FILE *fd; + char cmdline[MAXPGPATH]; + TimeLineID rtli = 0; + bool rtliGiven = false; + bool syntaxError = false; + + fd = AllocateFile(RECOVERY_COMMAND_FILE, "r"); + if (fd == NULL) + { + if (errno == ENOENT) + return; /* not there, so no archive recovery */ + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not open recovery command file \"%s\": %m", + RECOVERY_COMMAND_FILE))); + } + + ereport(LOG, + (errmsg("starting archive recovery"))); + + /* + * Parse the file... + */ + while (fgets(cmdline, sizeof(cmdline), fd) != NULL) + { + /* skip leading whitespace and check for # comment */ + char *ptr; + char *tok1; + char *tok2; + + for (ptr = cmdline; *ptr; ptr++) + { + if (!isspace((unsigned char) *ptr)) + break; + } + if (*ptr == '\0' || *ptr == '#') + continue; + + /* identify the quoted parameter value */ + tok1 = strtok(ptr, "'"); + if (!tok1) + { + syntaxError = true; + break; + } + tok2 = strtok(NULL, "'"); + if (!tok2) + { + syntaxError = true; + break; + } + /* reparse to get just the parameter name */ + tok1 = strtok(ptr, " \t="); + if (!tok1) + { + syntaxError = true; + break; + } + + if (strcmp(tok1, "restore_command") == 0) + { + recoveryRestoreCommand = pstrdup(tok2); + ereport(LOG, + (errmsg("restore_command = '%s'", + recoveryRestoreCommand))); + } + else if (strcmp(tok1, "recovery_target_timeline") == 0) + { + rtliGiven = true; + if (strcmp(tok2, "latest") == 0) + rtli = 0; + else + { + errno = 0; + rtli = (TimeLineID) strtoul(tok2, NULL, 0); + if (errno == EINVAL || errno == ERANGE) + ereport(FATAL, + (errmsg("recovery_target_timeline is not a valid number: \"%s\"", + tok2))); + } + if (rtli) + ereport(LOG, + (errmsg("recovery_target_timeline = %u", rtli))); + else + ereport(LOG, + (errmsg("recovery_target_timeline = latest"))); + } + else if (strcmp(tok1, "recovery_target_xid") == 0) + { + errno = 0; + recoveryTargetXid = (TransactionId) strtoul(tok2, NULL, 0); + if (errno == EINVAL || errno == ERANGE) + ereport(FATAL, + (errmsg("recovery_target_xid is not a valid number: \"%s\"", + tok2))); + ereport(LOG, + (errmsg("recovery_target_xid = %u", + recoveryTargetXid))); + recoveryTarget = true; + recoveryTargetExact = true; + } + else if (strcmp(tok1, "recovery_target_time") == 0) + { + /* + * if recovery_target_xid specified, then this overrides + * recovery_target_time + */ + if (recoveryTargetExact) + continue; + recoveryTarget = true; + recoveryTargetExact = false; + + /* + * Convert the time string given by the user to TimestampTz form. + */ + recoveryTargetTime = + DatumGetTimestampTz(DirectFunctionCall3(timestamptz_in, + CStringGetDatum(tok2), + ObjectIdGetDatum(InvalidOid), + Int32GetDatum(-1))); + ereport(LOG, + (errmsg("recovery_target_time = '%s'", + timestamptz_to_str(recoveryTargetTime)))); + } + else if (strcmp(tok1, "recovery_target_inclusive") == 0) + { + /* + * does nothing if a recovery_target is not also set + */ + if (!parse_bool(tok2, &recoveryTargetInclusive)) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("parameter \"recovery_target_inclusive\" requires a Boolean value"))); + ereport(LOG, + (errmsg("recovery_target_inclusive = %s", tok2))); + } + else if (strcmp(tok1, "log_restartpoints") == 0) + { + /* + * does nothing if a recovery_target is not also set + */ + if (!parse_bool(tok2, &recoveryLogRestartpoints)) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("parameter \"log_restartpoints\" requires a Boolean value"))); + ereport(LOG, + (errmsg("log_restartpoints = %s", tok2))); + } + else + ereport(FATAL, + (errmsg("unrecognized recovery parameter \"%s\"", + tok1))); + } + + FreeFile(fd); + + if (syntaxError) + ereport(FATAL, + (errmsg("syntax error in recovery command file: %s", + cmdline), + errhint("Lines should have the format parameter = 'value'."))); + + /* Check that required parameters were supplied */ + if (recoveryRestoreCommand == NULL) + ereport(FATAL, + (errmsg("recovery command file \"%s\" did not specify restore_command", + RECOVERY_COMMAND_FILE))); + + /* Enable fetching from archive recovery area */ + InArchiveRecovery = true; + + /* + * If user specified recovery_target_timeline, validate it or compute the + * "latest" value. We can't do this until after we've gotten the restore + * command and set InArchiveRecovery, because we need to fetch timeline + * history files from the archive. + */ + if (rtliGiven) + { + if (rtli) + { + /* Timeline 1 does not have a history file, all else should */ + if (rtli != 1 && !existsTimeLineHistory(rtli)) + ereport(FATAL, + (errmsg("recovery target timeline %u does not exist", + rtli))); + recoveryTargetTLI = rtli; + } + else + { + /* We start the "latest" search from pg_control's timeline */ + recoveryTargetTLI = findNewestTimeLine(recoveryTargetTLI); + } + } + } + + /* + * Exit archive-recovery state + */ + static void + exitArchiveRecovery(TimeLineID endTLI, uint32 endLogId, uint32 endLogSeg) + { + char recoveryPath[MAXPGPATH]; + char xlogpath[MAXPGPATH]; + + /* + * We are no longer in archive recovery state. + */ + InArchiveRecovery = false; + + /* + * We should have the ending log segment currently open. Verify, and then + * close it (to avoid problems on Windows with trying to rename or delete + * an open file). + */ + Assert(readFile >= 0); + Assert(readId == endLogId); + Assert(readSeg == endLogSeg); + + close(readFile); + readFile = -1; + + /* + * If the segment was fetched from archival storage, we want to replace + * the existing xlog segment (if any) with the archival version. This is + * because whatever is in XLOGDIR is very possibly older than what we have + * from the archives, since it could have come from restoring a PGDATA + * backup. In any case, the archival version certainly is more + * descriptive of what our current database state is, because that is what + * we replayed from. + * + * Note that if we are establishing a new timeline, ThisTimeLineID is + * already set to the new value, and so we will create a new file instead + * of overwriting any existing file. (This is, in fact, always the case + * at present.) + */ + snprintf(recoveryPath, MAXPGPATH, XLOGDIR "/RECOVERYXLOG"); + XLogFilePath(xlogpath, ThisTimeLineID, endLogId, endLogSeg); + + if (restoredFromArchive) + { + ereport(DEBUG3, + (errmsg_internal("moving last restored xlog to \"%s\"", + xlogpath))); + unlink(xlogpath); /* might or might not exist */ + if (rename(recoveryPath, xlogpath) != 0) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\": %m", + recoveryPath, xlogpath))); + /* XXX might we need to fix permissions on the file? */ + } + else + { + /* + * If the latest segment is not archival, but there's still a + * RECOVERYXLOG laying about, get rid of it. + */ + unlink(recoveryPath); /* ignore any error */ + + /* + * If we are establishing a new timeline, we have to copy data from + * the last WAL segment of the old timeline to create a starting WAL + * segment for the new timeline. + */ + if (endTLI != ThisTimeLineID) + XLogFileCopy(endLogId, endLogSeg, + endTLI, endLogId, endLogSeg); + } + + /* + * Let's just make real sure there are not .ready or .done flags posted + * for the new segment. + */ + XLogFileName(xlogpath, ThisTimeLineID, endLogId, endLogSeg); + XLogArchiveCleanup(xlogpath); + + /* Get rid of any remaining recovered timeline-history file, too */ + snprintf(recoveryPath, MAXPGPATH, XLOGDIR "/RECOVERYHISTORY"); + unlink(recoveryPath); /* ignore any error */ + + /* + * Rename the config file out of the way, so that we don't accidentally + * re-enter archive recovery mode in a subsequent crash. + */ + unlink(RECOVERY_COMMAND_DONE); + if (rename(RECOVERY_COMMAND_FILE, RECOVERY_COMMAND_DONE) != 0) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\": %m", + RECOVERY_COMMAND_FILE, RECOVERY_COMMAND_DONE))); + + ereport(LOG, + (errmsg("archive recovery complete"))); + } + + /* + * For point-in-time recovery, this function decides whether we want to + * stop applying the XLOG at or after the current record. + * + * Returns TRUE if we are stopping, FALSE otherwise. On TRUE return, + * *includeThis is set TRUE if we should apply this record before stopping. + * + * We also track the timestamp of the latest applied COMMIT/ABORT record + * in recoveryLastXTime, for logging purposes. + * Also, some information is saved in recoveryStopXid et al for use in + * annotating the new timeline's history file. + */ + static bool + recoveryStopsHere(XLogRecord *record, bool *includeThis) + { + bool stopsHere; + uint8 record_info; + TimestampTz recordXtime; + + /* We only consider stopping at COMMIT or ABORT records */ + if (record->xl_rmid != RM_XACT_ID) + return false; + record_info = record->xl_info & ~XLR_INFO_MASK; + if (record_info == XLOG_XACT_COMMIT) + { + xl_xact_commit *recordXactCommitData; + + recordXactCommitData = (xl_xact_commit *) XLogRecGetData(record); + recordXtime = recordXactCommitData->xact_time; + } + else if (record_info == XLOG_XACT_ABORT) + { + xl_xact_abort *recordXactAbortData; + + recordXactAbortData = (xl_xact_abort *) XLogRecGetData(record); + recordXtime = recordXactAbortData->xact_time; + } + else + return false; + + /* Do we have a PITR target at all? */ + if (!recoveryTarget) + { + recoveryLastXTime = recordXtime; + return false; + } + + if (recoveryTargetExact) + { + /* + * there can be only one transaction end record with this exact + * transactionid + * + * when testing for an xid, we MUST test for equality only, since + * transactions are numbered in the order they start, not the order + * they complete. A higher numbered xid will complete before you about + * 50% of the time... + */ + stopsHere = (record->xl_xid == recoveryTargetXid); + if (stopsHere) + *includeThis = recoveryTargetInclusive; + } + else + { + /* + * there can be many transactions that share the same commit time, so + * we stop after the last one, if we are inclusive, or stop at the + * first one if we are exclusive + */ + if (recoveryTargetInclusive) + stopsHere = (recordXtime > recoveryTargetTime); + else + stopsHere = (recordXtime >= recoveryTargetTime); + if (stopsHere) + *includeThis = false; + } + + if (stopsHere) + { + recoveryStopXid = record->xl_xid; + recoveryStopTime = recordXtime; + recoveryStopAfter = *includeThis; + + if (record_info == XLOG_XACT_COMMIT) + { + if (recoveryStopAfter) + ereport(LOG, + (errmsg("recovery stopping after commit of transaction %u, time %s", + recoveryStopXid, + timestamptz_to_str(recoveryStopTime)))); + else + ereport(LOG, + (errmsg("recovery stopping before commit of transaction %u, time %s", + recoveryStopXid, + timestamptz_to_str(recoveryStopTime)))); + } + else + { + if (recoveryStopAfter) + ereport(LOG, + (errmsg("recovery stopping after abort of transaction %u, time %s", + recoveryStopXid, + timestamptz_to_str(recoveryStopTime)))); + else + ereport(LOG, + (errmsg("recovery stopping before abort of transaction %u, time %s", + recoveryStopXid, + timestamptz_to_str(recoveryStopTime)))); + } + + if (recoveryStopAfter) + recoveryLastXTime = recordXtime; + } + else + recoveryLastXTime = recordXtime; + + return stopsHere; + } + + /* + * This must be called ONCE during postmaster or standalone-backend startup + */ + void + StartupXLOG(void) + { + XLogCtlInsert *Insert; + CheckPoint checkPoint; + bool wasShutdown; + bool reachedStopPoint = false; + bool haveBackupLabel = false; + XLogRecPtr RecPtr, + LastRec, + checkPointLoc, + minRecoveryLoc, + EndOfLog; + uint32 endLogId; + uint32 endLogSeg; + XLogRecord *record; + uint32 freespace; + TransactionId oldestActiveXID; + + /* + * Read control file and check XLOG status looks valid. + * + * Note: in most control paths, *ControlFile is already valid and we need + * not do ReadControlFile() here, but might as well do it to be sure. + */ + ReadControlFile(); + + if (ControlFile->state < DB_SHUTDOWNED || + ControlFile->state > DB_IN_PRODUCTION || + !XRecOffIsValid(ControlFile->checkPoint.xrecoff)) + ereport(FATAL, + (errmsg("control file contains invalid data"))); + + if (ControlFile->state == DB_SHUTDOWNED) + ereport(LOG, + (errmsg("database system was shut down at %s", + str_time(ControlFile->time)))); + else if (ControlFile->state == DB_SHUTDOWNING) + ereport(LOG, + (errmsg("database system shutdown was interrupted; last known up at %s", + str_time(ControlFile->time)))); + else if (ControlFile->state == DB_IN_CRASH_RECOVERY) + ereport(LOG, + (errmsg("database system was interrupted while in recovery at %s", + str_time(ControlFile->time)), + errhint("This probably means that some data is corrupted and" + " you will have to use the last backup for recovery."))); + else if (ControlFile->state == DB_IN_ARCHIVE_RECOVERY) + ereport(LOG, + (errmsg("database system was interrupted while in recovery at log time %s", + str_time(ControlFile->checkPointCopy.time)), + errhint("If this has occurred more than once some data might be corrupted" + " and you might need to choose an earlier recovery target."))); + else if (ControlFile->state == DB_IN_PRODUCTION) + ereport(LOG, + (errmsg("database system was interrupted; last known up at %s", + str_time(ControlFile->time)))); + + /* This is just to allow attaching to startup process with a debugger */ + #ifdef XLOG_REPLAY_DELAY + if (ControlFile->state != DB_SHUTDOWNED) + pg_usleep(60000000L); + #endif + + /* + * Verify that pg_xlog and pg_xlog/archive_status exist. In cases where + * someone has performed a copy for PITR, these directories may have + * been excluded and need to be re-created. + */ + ValidateXLOGDirectoryStructure(); + + /* + * To postpone the actual redo, store WAL records and EndRecPtrs. + * Therefore, this buffer must be allocated here because the buffer + * will be used by RedoRecords(); ReadRecord() may call RedoRecords(). + */ + RecordQueueBuf = (char *) malloc(RECORD_QUEUE_BUF_SIZE); + Assert(RecordQueueBuf != NULL); + + /* Allocate the buffer for storing information about data pages. */ + ReadAheadInit(); + + /* + * Initialize on the assumption we want to recover to the same timeline + * that's active according to pg_control. + */ + recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID; + + /* + * Check for recovery control file, and if so set up state for offline + * recovery + */ + readRecoveryCommandFile(); + + /* Now we can determine the list of expected TLIs */ + expectedTLIs = readTimeLineHistory(recoveryTargetTLI); + + /* + * If pg_control's timeline is not in expectedTLIs, then we cannot + * proceed: the backup is not part of the history of the requested + * timeline. + */ + if (!list_member_int(expectedTLIs, + (int) ControlFile->checkPointCopy.ThisTimeLineID)) + ereport(FATAL, + (errmsg("requested timeline %u is not a child of database system timeline %u", + recoveryTargetTLI, + ControlFile->checkPointCopy.ThisTimeLineID))); + + if (read_backup_label(&checkPointLoc, &minRecoveryLoc)) + { + /* + * When a backup_label file is present, we want to roll forward from + * the checkpoint it identifies, rather than using pg_control. + */ + record = ReadCheckpointRecord(checkPointLoc, 0); + if (record != NULL) + { + ereport(DEBUG1, + (errmsg("checkpoint record is at %X/%X", + checkPointLoc.xlogid, checkPointLoc.xrecoff))); + InRecovery = true; /* force recovery even if SHUTDOWNED */ + } + else + { + ereport(PANIC, + (errmsg("could not locate required checkpoint record"), + errhint("If you are not restoring from a backup, try removing the file \"%s/backup_label\".", DataDir))); + } + /* set flag to delete it later */ + haveBackupLabel = true; + } + else + { + /* + * Get the last valid checkpoint record. If the latest one according + * to pg_control is broken, try the next-to-last one. + */ + checkPointLoc = ControlFile->checkPoint; + record = ReadCheckpointRecord(checkPointLoc, 1); + if (record != NULL) + { + ereport(DEBUG1, + (errmsg("checkpoint record is at %X/%X", + checkPointLoc.xlogid, checkPointLoc.xrecoff))); + } + else + { + checkPointLoc = ControlFile->prevCheckPoint; + record = ReadCheckpointRecord(checkPointLoc, 2); + if (record != NULL) + { + ereport(LOG, + (errmsg("using previous checkpoint record at %X/%X", + checkPointLoc.xlogid, checkPointLoc.xrecoff))); + InRecovery = true; /* force recovery even if SHUTDOWNED */ + } + else + ereport(PANIC, + (errmsg("could not locate a valid checkpoint record"))); + } + } + + LastRec = RecPtr = checkPointLoc; + memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint)); + wasShutdown = (record->xl_info == XLOG_CHECKPOINT_SHUTDOWN); + + ereport(DEBUG1, + (errmsg("redo record is at %X/%X; shutdown %s", + checkPoint.redo.xlogid, checkPoint.redo.xrecoff, + wasShutdown ? "TRUE" : "FALSE"))); + ereport(DEBUG1, + (errmsg("next transaction ID: %u/%u; next OID: %u", + checkPoint.nextXidEpoch, checkPoint.nextXid, + checkPoint.nextOid))); + ereport(DEBUG1, + (errmsg("next MultiXactId: %u; next MultiXactOffset: %u", + checkPoint.nextMulti, checkPoint.nextMultiOffset))); + if (!TransactionIdIsNormal(checkPoint.nextXid)) + ereport(PANIC, + (errmsg("invalid next transaction ID"))); + + ShmemVariableCache->nextXid = checkPoint.nextXid; + ShmemVariableCache->nextOid = checkPoint.nextOid; + ShmemVariableCache->oidCount = 0; + MultiXactSetNextMXact(checkPoint.nextMulti, checkPoint.nextMultiOffset); + + /* + * We must replay WAL entries using the same TimeLineID they were created + * under, so temporarily adopt the TLI indicated by the checkpoint (see + * also xlog_redo()). + */ + ThisTimeLineID = checkPoint.ThisTimeLineID; + + RedoRecPtr = XLogCtl->Insert.RedoRecPtr = checkPoint.redo; + + if (XLByteLT(RecPtr, checkPoint.redo)) + ereport(PANIC, + (errmsg("invalid redo in checkpoint record"))); + + /* + * Check whether we need to force recovery from WAL. If it appears to + * have been a clean shutdown and we did not have a recovery.conf file, + * then assume no recovery needed. + */ + if (XLByteLT(checkPoint.redo, RecPtr)) + { + if (wasShutdown) + ereport(PANIC, + (errmsg("invalid redo record in shutdown checkpoint"))); + InRecovery = true; + } + else if (ControlFile->state != DB_SHUTDOWNED) + InRecovery = true; + else if (InArchiveRecovery) + { + /* force recovery due to presence of recovery.conf */ + InRecovery = true; + } + + /* REDO */ + if (InRecovery) + { + int rmid; + + /* + * Update pg_control to show that we are recovering and to show the + * selected checkpoint as the place we are starting from. We also mark + * pg_control with any minimum recovery stop point obtained from a + * backup history file. + */ + if (InArchiveRecovery) + { + ereport(LOG, + (errmsg("automatic recovery in progress"))); + ControlFile->state = DB_IN_ARCHIVE_RECOVERY; + } + else + { + ereport(LOG, + (errmsg("database system was not properly shut down; " + "automatic recovery in progress"))); + ControlFile->state = DB_IN_CRASH_RECOVERY; + } + ControlFile->prevCheckPoint = ControlFile->checkPoint; + ControlFile->checkPoint = checkPointLoc; + ControlFile->checkPointCopy = checkPoint; + if (minRecoveryLoc.xlogid != 0 || minRecoveryLoc.xrecoff != 0) + ControlFile->minRecoveryPoint = minRecoveryLoc; + ControlFile->time = (pg_time_t) time(NULL); + UpdateControlFile(); + + /* + * If there was a backup label file, it's done its job and the info + * has now been propagated into pg_control. We must get rid of the + * label file so that if we crash during recovery, we'll pick up at + * the latest recovery restartpoint instead of going all the way back + * to the backup start point. It seems prudent though to just rename + * the file out of the way rather than delete it completely. + */ + if (haveBackupLabel) + { + unlink(BACKUP_LABEL_OLD); + if (rename(BACKUP_LABEL_FILE, BACKUP_LABEL_OLD) != 0) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\": %m", + BACKUP_LABEL_FILE, BACKUP_LABEL_OLD))); + } + + /* Initialize resource managers */ + for (rmid = 0; rmid <= RM_MAX_ID; rmid++) + { + if (RmgrTable[rmid].rm_startup != NULL) + RmgrTable[rmid].rm_startup(); + } + + /* + * Find the first record that logically follows the checkpoint --- it + * might physically precede it, though. + */ + if (XLByteLT(checkPoint.redo, RecPtr)) + { + /* back up to find the record */ + record = ReadRecord(&(checkPoint.redo), PANIC); + } + else + { + /* just have to read next record after CheckPoint */ + record = ReadRecord(NULL, LOG); + } + + if (record != NULL) + { + bool recoveryContinue = true; + bool recoveryApply = true; + ErrorContextCallback errcontext; + + InRedo = true; + ereport(LOG, + (errmsg("redo starts at %X/%X", + ReadRecPtr.xlogid, ReadRecPtr.xrecoff))); + + /* + * main redo apply loop + */ + do + { + #ifdef WAL_DEBUG + if (XLOG_DEBUG) + { + StringInfoData buf; + + initStringInfo(&buf); + appendStringInfo(&buf, "REDO @ %X/%X; LSN %X/%X: ", + ReadRecPtr.xlogid, ReadRecPtr.xrecoff, + EndRecPtr.xlogid, EndRecPtr.xrecoff); + xlog_outrec(&buf, record); + appendStringInfo(&buf, " - "); + RmgrTable[record->xl_rmid].rm_desc(&buf, + record->xl_info, + XLogRecGetData(record)); + elog(LOG, "%s", buf.data); + pfree(buf.data); + } + #endif + + /* + * Have we reached our recovery target? + */ + if (recoveryStopsHere(record, &recoveryApply)) + { + reachedStopPoint = true; /* see below */ + recoveryContinue = false; + if (!recoveryApply) + break; + } + + /* Setup error traceback support for ereport() */ + errcontext.callback = rm_redo_error_callback; + errcontext.arg = (void *) record; + errcontext.previous = error_context_stack; + error_context_stack = &errcontext; + + /* nextXid must be beyond record's xid */ + if (TransactionIdFollowsOrEquals(record->xl_xid, + ShmemVariableCache->nextXid)) + { + ShmemVariableCache->nextXid = record->xl_xid; + TransactionIdAdvance(ShmemVariableCache->nextXid); + } + + /* + * Push WAL record in WAL record buffer with its LSN for + * delayed redo. + * If the WAL record queue is full, redo all WAL records in the + * queue and make the queue empty. + */ + ereport(DEBUG1, + (errmsg("WAL record queue is used %d(%d) bytes at %X/%08X.", + RecordQueueBufUsed, record->xl_tot_len, + EndRecPtr.xlogid, EndRecPtr.xrecoff))); + PushRecord(EndRecPtr, record); + + /* + * Push page information to prefetch later. + * If no more space, redo all records in queue and make the + * queue empty. + */ + PushReadAhead(EndRecPtr, record); + + LastRec = ReadRecPtr; + + record = ReadRecord(NULL, LOG); + } while (record != NULL && recoveryContinue); + + /* All WAL records are read, redo all queued WAL records. */ + ereport(DEBUG1, (errmsg("end of redo apply loop"))); + RedoRecords(); + + /* + * end of main redo apply loop + */ + + ereport(LOG, + (errmsg("redo done at %X/%X", + ReadRecPtr.xlogid, ReadRecPtr.xrecoff))); + if (recoveryLastXTime) + ereport(LOG, + (errmsg("last completed transaction was at log time %s", + timestamptz_to_str(recoveryLastXTime)))); + InRedo = false; + } + else + { + /* there are no WAL records following the checkpoint */ + ereport(LOG, + (errmsg("redo is not required"))); + } + } + + /* + * Re-fetch the last valid or last applied record, so we can identify the + * exact endpoint of what we consider the valid portion of WAL. + */ + record = ReadRecord(&LastRec, PANIC); + EndOfLog = EndRecPtr; + XLByteToPrevSeg(EndOfLog, endLogId, endLogSeg); + + /* + * Complain if we did not roll forward far enough to render the backup + * dump consistent. + */ + if (XLByteLT(EndOfLog, ControlFile->minRecoveryPoint)) + { + if (reachedStopPoint) /* stopped because of stop request */ + ereport(FATAL, + (errmsg("requested recovery stop point is before end time of backup dump"))); + else /* ran off end of WAL */ + ereport(FATAL, + (errmsg("WAL ends before end time of backup dump"))); + } + + /* + * Consider whether we need to assign a new timeline ID. + * + * If we are doing an archive recovery, we always assign a new ID. This + * handles a couple of issues. If we stopped short of the end of WAL + * during recovery, then we are clearly generating a new timeline and must + * assign it a unique new ID. Even if we ran to the end, modifying the + * current last segment is problematic because it may result in trying to + * overwrite an already-archived copy of that segment, and we encourage + * DBAs to make their archive_commands reject that. We can dodge the + * problem by making the new active segment have a new timeline ID. + * + * In a normal crash recovery, we can just extend the timeline we were in. + */ + if (InArchiveRecovery) + { + ThisTimeLineID = findNewestTimeLine(recoveryTargetTLI) + 1; + ereport(LOG, + (errmsg("selected new timeline ID: %u", ThisTimeLineID))); + writeTimeLineHistory(ThisTimeLineID, recoveryTargetTLI, + curFileTLI, endLogId, endLogSeg); + } + + /* Save the selected TimeLineID in shared memory, too */ + XLogCtl->ThisTimeLineID = ThisTimeLineID; + + /* + * We are now done reading the old WAL. Turn off archive fetching if it + * was active, and make a writable copy of the last WAL segment. (Note + * that we also have a copy of the last block of the old WAL in readBuf; + * we will use that below.) + */ + if (InArchiveRecovery) + exitArchiveRecovery(curFileTLI, endLogId, endLogSeg); + + /* + * Prepare to write WAL starting at EndOfLog position, and init xlog + * buffer cache using the block containing the last record from the + * previous incarnation. + */ + openLogId = endLogId; + openLogSeg = endLogSeg; + openLogFile = XLogFileOpen(openLogId, openLogSeg); + openLogOff = 0; + Insert = &XLogCtl->Insert; + Insert->PrevRecord = LastRec; + XLogCtl->xlblocks[0].xlogid = openLogId; + XLogCtl->xlblocks[0].xrecoff = + ((EndOfLog.xrecoff - 1) / XLOG_BLCKSZ + 1) * XLOG_BLCKSZ; + + /* + * Tricky point here: readBuf contains the *last* block that the LastRec + * record spans, not the one it starts in. The last block is indeed the + * one we want to use. + */ + Assert(readOff == (XLogCtl->xlblocks[0].xrecoff - XLOG_BLCKSZ) % XLogSegSize); + memcpy((char *) Insert->currpage, readBuf, XLOG_BLCKSZ); + Insert->currpos = (char *) Insert->currpage + + (EndOfLog.xrecoff + XLOG_BLCKSZ - XLogCtl->xlblocks[0].xrecoff); + + LogwrtResult.Write = LogwrtResult.Flush = EndOfLog; + + XLogCtl->Write.LogwrtResult = LogwrtResult; + Insert->LogwrtResult = LogwrtResult; + XLogCtl->LogwrtResult = LogwrtResult; + + XLogCtl->LogwrtRqst.Write = EndOfLog; + XLogCtl->LogwrtRqst.Flush = EndOfLog; + + freespace = INSERT_FREESPACE(Insert); + if (freespace > 0) + { + /* Make sure rest of page is zero */ + MemSet(Insert->currpos, 0, freespace); + XLogCtl->Write.curridx = 0; + } + else + { + /* + * Whenever Write.LogwrtResult points to exactly the end of a page, + * Write.curridx must point to the *next* page (see XLogWrite()). + * + * Note: it might seem we should do AdvanceXLInsertBuffer() here, but + * this is sufficient. The first actual attempt to insert a log + * record will advance the insert state. + */ + XLogCtl->Write.curridx = NextBufIdx(0); + } + + /* Pre-scan prepared transactions to find out the range of XIDs present */ + oldestActiveXID = PrescanPreparedTransactions(); + + if (InRecovery) + { + int rmid; + + /* + * Allow resource managers to do any required cleanup. + */ + for (rmid = 0; rmid <= RM_MAX_ID; rmid++) + { + if (RmgrTable[rmid].rm_cleanup != NULL) + RmgrTable[rmid].rm_cleanup(); + } + + /* + * Check to see if the XLOG sequence contained any unresolved + * references to uninitialized pages. + */ + XLogCheckInvalidPages(); + + /* + * Reset pgstat data, because it may be invalid after recovery. + */ + pgstat_reset_all(); + + /* + * Perform a checkpoint to update all our recovery activity to disk. + * + * Note that we write a shutdown checkpoint rather than an on-line + * one. This is not particularly critical, but since we may be + * assigning a new TLI, using a shutdown checkpoint allows us to have + * the rule that TLI only changes in shutdown checkpoints, which + * allows some extra error checking in xlog_redo. + */ + CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE); + } + + /* + * Preallocate additional log files, if wanted. + */ + PreallocXlogFiles(EndOfLog); + + /* + * Okay, we're officially UP. + */ + InRecovery = false; + + ControlFile->state = DB_IN_PRODUCTION; + ControlFile->time = (pg_time_t) time(NULL); + UpdateControlFile(); + + /* start the archive_timeout timer running */ + XLogCtl->Write.lastSegSwitchTime = ControlFile->time; + + /* initialize shared-memory copy of latest checkpoint XID/epoch */ + XLogCtl->ckptXidEpoch = ControlFile->checkPointCopy.nextXidEpoch; + XLogCtl->ckptXid = ControlFile->checkPointCopy.nextXid; + + /* also initialize latestCompletedXid, to nextXid - 1 */ + ShmemVariableCache->latestCompletedXid = ShmemVariableCache->nextXid; + TransactionIdRetreat(ShmemVariableCache->latestCompletedXid); + + /* Start up the commit log and related stuff, too */ + StartupCLOG(); + StartupSUBTRANS(oldestActiveXID); + StartupMultiXact(); + + /* Reload shared-memory state for prepared transactions */ + RecoverPreparedTransactions(); + + /* Shut down readFile facility, free space */ + if (readFile >= 0) + { + close(readFile); + readFile = -1; + } + if (readBuf) + { + free(readBuf); + readBuf = NULL; + } + if (readRecordBuf) + { + free(readRecordBuf); + readRecordBuf = NULL; + readRecordBufSize = 0; + } + if (RecordQueueBuf) + { + free(RecordQueueBuf); + RecordQueueBufUsed = 0; + ReadAheadFinish(); + } + } + + /* + * Push the pair of WAL record and its LSN. + * Both WAL records and LSNs are aligned as same as WAL segment file. + */ + static void + PushRecord(XLogRecPtr lsn, XLogRecord *record) + { + Assert(record); + + if (RecordQueueBufUsed + MAXALIGN(sizeof(XLogRecPtr)) + + MAXALIGN(record->xl_tot_len) > RECORD_QUEUE_BUF_SIZE) + { + ereport(DEBUG1, (errmsg("WAL record queue is full."))); + RedoRecords(); + } + + memcpy(RecordQueueBuf + RecordQueueBufUsed, &lsn, sizeof(XLogRecPtr)); + RecordQueueBufUsed += MAXALIGN(sizeof(XLogRecPtr)); + memcpy(RecordQueueBuf + RecordQueueBufUsed, record, record->xl_tot_len); + RecordQueueBufUsed += MAXALIGN(record->xl_tot_len); + } + + /* + * Push page information to readahead module. + */ + static void + PushReadAhead(XLogRecPtr lsn, XLogRecord *record) + { + Assert(record); + + if (!RmgrTable[record->xl_rmid].rm_readahead) + return; + + while (!RmgrTable[record->xl_rmid].rm_readahead(lsn, record)) + { + ereport(DEBUG1, (errmsg("ReadAhead queue is full."))); + RedoRecords(); + } + } + + /* + * Redo all WAL records in the queue and make the it empty. + */ + static void + RedoRecords(void) + { + ErrorContextCallback errcontext; + uint32 off = 0; + + /* Readahead data pages which will be modified during redo. */ + ReadAheadExecute(); + + while (off < RecordQueueBufUsed) + { + XLogRecPtr lsn; + XLogRecord *record; + + /* Extract LSN and WAL record image from local buffer. */ + memcpy(&lsn, RecordQueueBuf + off, sizeof(XLogRecPtr)); + off += MAXALIGN(sizeof(XLogRecPtr)); + record = (XLogRecord *)(RecordQueueBuf + off); + + /* Setup error traceback support for ereport() */ + errcontext.callback = rm_redo_error_callback; + errcontext.arg = (void *) record; + errcontext.previous = error_context_stack; + error_context_stack = &errcontext; + + /* nextXid must be beyond record's xid */ + if (TransactionIdFollowsOrEquals(record->xl_xid, + ShmemVariableCache->nextXid)) + { + ShmemVariableCache->nextXid = record->xl_xid; + TransactionIdAdvance(ShmemVariableCache->nextXid); + } + + /* Redo with WAL record and its LSN. */ + RmgrTable[record->xl_rmid].rm_redo(lsn, record); + + /* Pop the error context stack */ + error_context_stack = errcontext.previous; + + off += MAXALIGN(record->xl_tot_len); + } + + /* Make RecordQueueBuf empty. */ + MemSet(RecordQueueBuf, 0, sizeof(RecordQueueBuf)); + RecordQueueBufUsed = 0; + } + + /* + * Subroutine to try to fetch and validate a prior checkpoint record. + * + * whichChkpt identifies the checkpoint (merely for reporting purposes). + * 1 for "primary", 2 for "secondary", 0 for "other" (backup_label) + */ + static XLogRecord * + ReadCheckpointRecord(XLogRecPtr RecPtr, int whichChkpt) + { + XLogRecord *record; + + if (!XRecOffIsValid(RecPtr.xrecoff)) + { + switch (whichChkpt) + { + case 1: + ereport(LOG, + (errmsg("invalid primary checkpoint link in control file"))); + break; + case 2: + ereport(LOG, + (errmsg("invalid secondary checkpoint link in control file"))); + break; + default: + ereport(LOG, + (errmsg("invalid checkpoint link in backup_label file"))); + break; + } + return NULL; + } + + record = ReadRecord(&RecPtr, LOG); + + if (record == NULL) + { + switch (whichChkpt) + { + case 1: + ereport(LOG, + (errmsg("invalid primary checkpoint record"))); + break; + case 2: + ereport(LOG, + (errmsg("invalid secondary checkpoint record"))); + break; + default: + ereport(LOG, + (errmsg("invalid checkpoint record"))); + break; + } + return NULL; + } + if (record->xl_rmid != RM_XLOG_ID) + { + switch (whichChkpt) + { + case 1: + ereport(LOG, + (errmsg("invalid resource manager ID in primary checkpoint record"))); + break; + case 2: + ereport(LOG, + (errmsg("invalid resource manager ID in secondary checkpoint record"))); + break; + default: + ereport(LOG, + (errmsg("invalid resource manager ID in checkpoint record"))); + break; + } + return NULL; + } + if (record->xl_info != XLOG_CHECKPOINT_SHUTDOWN && + record->xl_info != XLOG_CHECKPOINT_ONLINE) + { + switch (whichChkpt) + { + case 1: + ereport(LOG, + (errmsg("invalid xl_info in primary checkpoint record"))); + break; + case 2: + ereport(LOG, + (errmsg("invalid xl_info in secondary checkpoint record"))); + break; + default: + ereport(LOG, + (errmsg("invalid xl_info in checkpoint record"))); + break; + } + return NULL; + } + if (record->xl_len != sizeof(CheckPoint) || + record->xl_tot_len != SizeOfXLogRecord + sizeof(CheckPoint)) + { + switch (whichChkpt) + { + case 1: + ereport(LOG, + (errmsg("invalid length of primary checkpoint record"))); + break; + case 2: + ereport(LOG, + (errmsg("invalid length of secondary checkpoint record"))); + break; + default: + ereport(LOG, + (errmsg("invalid length of checkpoint record"))); + break; + } + return NULL; + } + return record; + } + + /* + * This must be called during startup of a backend process, except that + * it need not be called in a standalone backend (which does StartupXLOG + * instead). We need to initialize the local copies of ThisTimeLineID and + * RedoRecPtr. + * + * Note: before Postgres 8.0, we went to some effort to keep the postmaster + * process's copies of ThisTimeLineID and RedoRecPtr valid too. This was + * unnecessary however, since the postmaster itself never touches XLOG anyway. + */ + void + InitXLOGAccess(void) + { + /* ThisTimeLineID doesn't change so we need no lock to copy it */ + ThisTimeLineID = XLogCtl->ThisTimeLineID; + /* Use GetRedoRecPtr to copy the RedoRecPtr safely */ + (void) GetRedoRecPtr(); + } + + /* + * Once spawned, a backend may update its local RedoRecPtr from + * XLogCtl->Insert.RedoRecPtr; it must hold the insert lock or info_lck + * to do so. This is done in XLogInsert() or GetRedoRecPtr(). + */ + XLogRecPtr + GetRedoRecPtr(void) + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + Assert(XLByteLE(RedoRecPtr, xlogctl->Insert.RedoRecPtr)); + RedoRecPtr = xlogctl->Insert.RedoRecPtr; + SpinLockRelease(&xlogctl->info_lck); + + return RedoRecPtr; + } + + /* + * GetInsertRecPtr -- Returns the current insert position. + * + * NOTE: The value *actually* returned is the position of the last full + * xlog page. It lags behind the real insert position by at most 1 page. + * For that, we don't need to acquire WALInsertLock which can be quite + * heavily contended, and an approximation is enough for the current + * usage of this function. + */ + XLogRecPtr + GetInsertRecPtr(void) + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + XLogRecPtr recptr; + + SpinLockAcquire(&xlogctl->info_lck); + recptr = xlogctl->LogwrtRqst.Write; + SpinLockRelease(&xlogctl->info_lck); + + return recptr; + } + + /* + * Get the time of the last xlog segment switch + */ + pg_time_t + GetLastSegSwitchTime(void) + { + pg_time_t result; + + /* Need WALWriteLock, but shared lock is sufficient */ + LWLockAcquire(WALWriteLock, LW_SHARED); + result = XLogCtl->Write.lastSegSwitchTime; + LWLockRelease(WALWriteLock); + + return result; + } + + /* + * GetNextXidAndEpoch - get the current nextXid value and associated epoch + * + * This is exported for use by code that would like to have 64-bit XIDs. + * We don't really support such things, but all XIDs within the system + * can be presumed "close to" the result, and thus the epoch associated + * with them can be determined. + */ + void + GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch) + { + uint32 ckptXidEpoch; + TransactionId ckptXid; + TransactionId nextXid; + + /* Must read checkpoint info first, else have race condition */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + ckptXidEpoch = xlogctl->ckptXidEpoch; + ckptXid = xlogctl->ckptXid; + SpinLockRelease(&xlogctl->info_lck); + } + + /* Now fetch current nextXid */ + nextXid = ReadNewTransactionId(); + + /* + * nextXid is certainly logically later than ckptXid. So if it's + * numerically less, it must have wrapped into the next epoch. + */ + if (nextXid < ckptXid) + ckptXidEpoch++; + + *xid = nextXid; + *epoch = ckptXidEpoch; + } + + /* + * This must be called ONCE during postmaster or standalone-backend shutdown + */ + void + ShutdownXLOG(int code, Datum arg) + { + ereport(LOG, + (errmsg("shutting down"))); + + CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE); + ShutdownCLOG(); + ShutdownSUBTRANS(); + ShutdownMultiXact(); + + ereport(LOG, + (errmsg("database system is shut down"))); + } + + /* + * Log start of a checkpoint. + */ + static void + LogCheckpointStart(int flags) + { + elog(LOG, "checkpoint starting:%s%s%s%s%s%s", + (flags & CHECKPOINT_IS_SHUTDOWN) ? " shutdown" : "", + (flags & CHECKPOINT_IMMEDIATE) ? " immediate" : "", + (flags & CHECKPOINT_FORCE) ? " force" : "", + (flags & CHECKPOINT_WAIT) ? " wait" : "", + (flags & CHECKPOINT_CAUSE_XLOG) ? " xlog" : "", + (flags & CHECKPOINT_CAUSE_TIME) ? " time" : ""); + } + + /* + * Log end of a checkpoint. + */ + static void + LogCheckpointEnd(void) + { + long write_secs, + sync_secs, + total_secs; + int write_usecs, + sync_usecs, + total_usecs; + + CheckpointStats.ckpt_end_t = GetCurrentTimestamp(); + + TimestampDifference(CheckpointStats.ckpt_start_t, + CheckpointStats.ckpt_end_t, + &total_secs, &total_usecs); + + TimestampDifference(CheckpointStats.ckpt_write_t, + CheckpointStats.ckpt_sync_t, + &write_secs, &write_usecs); + + TimestampDifference(CheckpointStats.ckpt_sync_t, + CheckpointStats.ckpt_sync_end_t, + &sync_secs, &sync_usecs); + + elog(LOG, "checkpoint complete: wrote %d buffers (%.1f%%); " + "%d transaction log file(s) added, %d removed, %d recycled; " + "write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s", + CheckpointStats.ckpt_bufs_written, + (double) CheckpointStats.ckpt_bufs_written * 100 / NBuffers, + CheckpointStats.ckpt_segs_added, + CheckpointStats.ckpt_segs_removed, + CheckpointStats.ckpt_segs_recycled, + write_secs, write_usecs / 1000, + sync_secs, sync_usecs / 1000, + total_secs, total_usecs / 1000); + } + + /* + * Perform a checkpoint --- either during shutdown, or on-the-fly + * + * flags is a bitwise OR of the following: + * CHECKPOINT_IS_SHUTDOWN: checkpoint is for database shutdown. + * CHECKPOINT_IMMEDIATE: finish the checkpoint ASAP, + * ignoring checkpoint_completion_target parameter. + * CHECKPOINT_FORCE: force a checkpoint even if no XLOG activity has occured + * since the last one (implied by CHECKPOINT_IS_SHUTDOWN). + * + * Note: flags contains other bits, of interest here only for logging purposes. + * In particular note that this routine is synchronous and does not pay + * attention to CHECKPOINT_WAIT. + */ + void + CreateCheckPoint(int flags) + { + bool shutdown = (flags & CHECKPOINT_IS_SHUTDOWN) != 0; + CheckPoint checkPoint; + XLogRecPtr recptr; + XLogCtlInsert *Insert = &XLogCtl->Insert; + XLogRecData rdata; + uint32 freespace; + uint32 _logId; + uint32 _logSeg; + TransactionId *inCommitXids; + int nInCommit; + + /* + * Acquire CheckpointLock to ensure only one checkpoint happens at a time. + * (This is just pro forma, since in the present system structure there is + * only one process that is allowed to issue checkpoints at any given + * time.) + */ + LWLockAcquire(CheckpointLock, LW_EXCLUSIVE); + + /* + * Prepare to accumulate statistics. + * + * Note: because it is possible for log_checkpoints to change while a + * checkpoint proceeds, we always accumulate stats, even if + * log_checkpoints is currently off. + */ + MemSet(&CheckpointStats, 0, sizeof(CheckpointStats)); + CheckpointStats.ckpt_start_t = GetCurrentTimestamp(); + + /* + * Use a critical section to force system panic if we have trouble. + */ + START_CRIT_SECTION(); + + if (shutdown) + { + ControlFile->state = DB_SHUTDOWNING; + ControlFile->time = (pg_time_t) time(NULL); + UpdateControlFile(); + } + + /* + * Let smgr prepare for checkpoint; this has to happen before we determine + * the REDO pointer. Note that smgr must not do anything that'd have to + * be undone if we decide no checkpoint is needed. + */ + smgrpreckpt(); + + /* Begin filling in the checkpoint WAL record */ + MemSet(&checkPoint, 0, sizeof(checkPoint)); + checkPoint.ThisTimeLineID = ThisTimeLineID; + checkPoint.time = (pg_time_t) time(NULL); + + /* + * We must hold WALInsertLock while examining insert state to determine + * the checkpoint REDO pointer. + */ + LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); + + /* + * If this isn't a shutdown or forced checkpoint, and we have not inserted + * any XLOG records since the start of the last checkpoint, skip the + * checkpoint. The idea here is to avoid inserting duplicate checkpoints + * when the system is idle. That wastes log space, and more importantly it + * exposes us to possible loss of both current and previous checkpoint + * records if the machine crashes just as we're writing the update. + * (Perhaps it'd make even more sense to checkpoint only when the previous + * checkpoint record is in a different xlog page?) + * + * We have to make two tests to determine that nothing has happened since + * the start of the last checkpoint: current insertion point must match + * the end of the last checkpoint record, and its redo pointer must point + * to itself. + */ + if ((flags & (CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_FORCE)) == 0) + { + XLogRecPtr curInsert; + + INSERT_RECPTR(curInsert, Insert, Insert->curridx); + if (curInsert.xlogid == ControlFile->checkPoint.xlogid && + curInsert.xrecoff == ControlFile->checkPoint.xrecoff + + MAXALIGN(SizeOfXLogRecord + sizeof(CheckPoint)) && + ControlFile->checkPoint.xlogid == + ControlFile->checkPointCopy.redo.xlogid && + ControlFile->checkPoint.xrecoff == + ControlFile->checkPointCopy.redo.xrecoff) + { + LWLockRelease(WALInsertLock); + LWLockRelease(CheckpointLock); + END_CRIT_SECTION(); + return; + } + } + + /* + * Compute new REDO record ptr = location of next XLOG record. + * + * NB: this is NOT necessarily where the checkpoint record itself will be, + * since other backends may insert more XLOG records while we're off doing + * the buffer flush work. Those XLOG records are logically after the + * checkpoint, even though physically before it. Got that? + */ + freespace = INSERT_FREESPACE(Insert); + if (freespace < SizeOfXLogRecord) + { + (void) AdvanceXLInsertBuffer(false); + /* OK to ignore update return flag, since we will do flush anyway */ + freespace = INSERT_FREESPACE(Insert); + } + INSERT_RECPTR(checkPoint.redo, Insert, Insert->curridx); + + /* + * Here we update the shared RedoRecPtr for future XLogInsert calls; this + * must be done while holding the insert lock AND the info_lck. + * + * Note: if we fail to complete the checkpoint, RedoRecPtr will be left + * pointing past where it really needs to point. This is okay; the only + * consequence is that XLogInsert might back up whole buffers that it + * didn't really need to. We can't postpone advancing RedoRecPtr because + * XLogInserts that happen while we are dumping buffers must assume that + * their buffer changes are not included in the checkpoint. + */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + RedoRecPtr = xlogctl->Insert.RedoRecPtr = checkPoint.redo; + SpinLockRelease(&xlogctl->info_lck); + } + + /* + * Now we can release WAL insert lock, allowing other xacts to proceed + * while we are flushing disk buffers. + */ + LWLockRelease(WALInsertLock); + + /* + * If enabled, log checkpoint start. We postpone this until now so as not + * to log anything if we decided to skip the checkpoint. + */ + if (log_checkpoints) + LogCheckpointStart(flags); + + TRACE_POSTGRESQL_CHECKPOINT_START(flags); + + /* + * Before flushing data, we must wait for any transactions that are + * currently in their commit critical sections. If an xact inserted its + * commit record into XLOG just before the REDO point, then a crash + * restart from the REDO point would not replay that record, which means + * that our flushing had better include the xact's update of pg_clog. So + * we wait till he's out of his commit critical section before proceeding. + * See notes in RecordTransactionCommit(). + * + * Because we've already released WALInsertLock, this test is a bit fuzzy: + * it is possible that we will wait for xacts we didn't really need to + * wait for. But the delay should be short and it seems better to make + * checkpoint take a bit longer than to hold locks longer than necessary. + * (In fact, the whole reason we have this issue is that xact.c does + * commit record XLOG insertion and clog update as two separate steps + * protected by different locks, but again that seems best on grounds of + * minimizing lock contention.) + * + * A transaction that has not yet set inCommit when we look cannot be at + * risk, since he's not inserted his commit record yet; and one that's + * already cleared it is not at risk either, since he's done fixing clog + * and we will correctly flush the update below. So we cannot miss any + * xacts we need to wait for. + */ + nInCommit = GetTransactionsInCommit(&inCommitXids); + if (nInCommit > 0) + { + do + { + pg_usleep(10000L); /* wait for 10 msec */ + } while (HaveTransactionsInCommit(inCommitXids, nInCommit)); + } + pfree(inCommitXids); + + /* + * Get the other info we need for the checkpoint record. + */ + LWLockAcquire(XidGenLock, LW_SHARED); + checkPoint.nextXid = ShmemVariableCache->nextXid; + LWLockRelease(XidGenLock); + + /* Increase XID epoch if we've wrapped around since last checkpoint */ + checkPoint.nextXidEpoch = ControlFile->checkPointCopy.nextXidEpoch; + if (checkPoint.nextXid < ControlFile->checkPointCopy.nextXid) + checkPoint.nextXidEpoch++; + + LWLockAcquire(OidGenLock, LW_SHARED); + checkPoint.nextOid = ShmemVariableCache->nextOid; + if (!shutdown) + checkPoint.nextOid += ShmemVariableCache->oidCount; + LWLockRelease(OidGenLock); + + MultiXactGetCheckptMulti(shutdown, + &checkPoint.nextMulti, + &checkPoint.nextMultiOffset); + + /* + * Having constructed the checkpoint record, ensure all shmem disk buffers + * and commit-log buffers are flushed to disk. + * + * This I/O could fail for various reasons. If so, we will fail to + * complete the checkpoint, but there is no reason to force a system + * panic. Accordingly, exit critical section while doing it. + */ + END_CRIT_SECTION(); + + CheckPointGuts(checkPoint.redo, flags); + + START_CRIT_SECTION(); + + /* + * Now insert the checkpoint record into XLOG. + */ + rdata.data = (char *) (&checkPoint); + rdata.len = sizeof(checkPoint); + rdata.buffer = InvalidBuffer; + rdata.next = NULL; + + recptr = XLogInsert(RM_XLOG_ID, + shutdown ? XLOG_CHECKPOINT_SHUTDOWN : + XLOG_CHECKPOINT_ONLINE, + &rdata); + + XLogFlush(recptr); + + /* + * We now have ProcLastRecPtr = start of actual checkpoint record, recptr + * = end of actual checkpoint record. + */ + if (shutdown && !XLByteEQ(checkPoint.redo, ProcLastRecPtr)) + ereport(PANIC, + (errmsg("concurrent transaction log activity while database system is shutting down"))); + + /* + * Select point at which we can truncate the log, which we base on the + * prior checkpoint's earliest info. + */ + XLByteToSeg(ControlFile->checkPointCopy.redo, _logId, _logSeg); + + /* + * Update the control file. + */ + LWLockAcquire(ControlFileLock, LW_EXCLUSIVE); + if (shutdown) + ControlFile->state = DB_SHUTDOWNED; + ControlFile->prevCheckPoint = ControlFile->checkPoint; + ControlFile->checkPoint = ProcLastRecPtr; + ControlFile->checkPointCopy = checkPoint; + ControlFile->time = (pg_time_t) time(NULL); + UpdateControlFile(); + LWLockRelease(ControlFileLock); + + /* Update shared-memory copy of checkpoint XID/epoch */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + xlogctl->ckptXidEpoch = checkPoint.nextXidEpoch; + xlogctl->ckptXid = checkPoint.nextXid; + SpinLockRelease(&xlogctl->info_lck); + } + + /* + * We are now done with critical updates; no need for system panic if we + * have trouble while fooling with old log segments. + */ + END_CRIT_SECTION(); + + /* + * Let smgr do post-checkpoint cleanup (eg, deleting old files). + */ + smgrpostckpt(); + + /* + * Delete old log files (those no longer needed even for previous + * checkpoint). + */ + if (_logId || _logSeg) + { + PrevLogSeg(_logId, _logSeg); + RemoveOldXlogFiles(_logId, _logSeg, recptr); + } + + /* + * Make more log segments if needed. (Do this after recycling old log + * segments, since that may supply some of the needed files.) + */ + if (!shutdown) + PreallocXlogFiles(recptr); + + /* + * Truncate pg_subtrans if possible. We can throw away all data before + * the oldest XMIN of any running transaction. No future transaction will + * attempt to reference any pg_subtrans entry older than that (see Asserts + * in subtrans.c). During recovery, though, we mustn't do this because + * StartupSUBTRANS hasn't been called yet. + */ + if (!InRecovery) + TruncateSUBTRANS(GetOldestXmin(true, false)); + + /* All real work is done, but log before releasing lock. */ + if (log_checkpoints) + LogCheckpointEnd(); + + TRACE_POSTGRESQL_CHECKPOINT_DONE(CheckpointStats.ckpt_bufs_written, + NBuffers, CheckpointStats.ckpt_segs_added, + CheckpointStats.ckpt_segs_removed, + CheckpointStats.ckpt_segs_recycled); + + LWLockRelease(CheckpointLock); + } + + /* + * Flush all data in shared memory to disk, and fsync + * + * This is the common code shared between regular checkpoints and + * recovery restartpoints. + */ + static void + CheckPointGuts(XLogRecPtr checkPointRedo, int flags) + { + CheckPointCLOG(); + CheckPointSUBTRANS(); + CheckPointMultiXact(); + CheckPointBuffers(flags); /* performs all required fsyncs */ + /* We deliberately delay 2PC checkpointing as long as possible */ + CheckPointTwoPhase(checkPointRedo); + } + + /* + * Set a recovery restart point if appropriate + * + * This is similar to CreateCheckPoint, but is used during WAL recovery + * to establish a point from which recovery can roll forward without + * replaying the entire recovery log. This function is called each time + * a checkpoint record is read from XLOG; it must determine whether a + * restartpoint is needed or not. + */ + static void + RecoveryRestartPoint(const CheckPoint *checkPoint) + { + int elapsed_secs; + int rmid; + + /* + * Do nothing if the elapsed time since the last restartpoint is less than + * half of checkpoint_timeout. (We use a value less than + * checkpoint_timeout so that variations in the timing of checkpoints on + * the master, or speed of transmission of WAL segments to a slave, won't + * make the slave skip a restartpoint once it's synced with the master.) + * Checking true elapsed time keeps us from doing restartpoints too often + * while rapidly scanning large amounts of WAL. + */ + elapsed_secs = (pg_time_t) time(NULL) - ControlFile->time; + if (elapsed_secs < CheckPointTimeout / 2) + return; + + /* + * Is it safe to checkpoint? We must ask each of the resource managers + * whether they have any partial state information that might prevent a + * correct restart from this point. If so, we skip this opportunity, but + * return at the next checkpoint record for another try. + */ + for (rmid = 0; rmid <= RM_MAX_ID; rmid++) + { + if (RmgrTable[rmid].rm_safe_restartpoint != NULL) + if (!(RmgrTable[rmid].rm_safe_restartpoint())) + { + elog(DEBUG2, "RM %d not safe to record restart point at %X/%X", + rmid, + checkPoint->redo.xlogid, + checkPoint->redo.xrecoff); + return; + } + } + + /* + * OK, force data out to disk + */ + CheckPointGuts(checkPoint->redo, CHECKPOINT_IMMEDIATE); + + /* + * Update pg_control so that any subsequent crash will restart from this + * checkpoint. Note: ReadRecPtr gives the XLOG address of the checkpoint + * record itself. + */ + ControlFile->prevCheckPoint = ControlFile->checkPoint; + ControlFile->checkPoint = ReadRecPtr; + ControlFile->checkPointCopy = *checkPoint; + ControlFile->time = (pg_time_t) time(NULL); + UpdateControlFile(); + + ereport((recoveryLogRestartpoints ? LOG : DEBUG2), + (errmsg("recovery restart point at %X/%X", + checkPoint->redo.xlogid, checkPoint->redo.xrecoff))); + if (recoveryLastXTime) + ereport((recoveryLogRestartpoints ? LOG : DEBUG2), + (errmsg("last completed transaction was at log time %s", + timestamptz_to_str(recoveryLastXTime)))); + } + + /* + * Write a NEXTOID log record + */ + void + XLogPutNextOid(Oid nextOid) + { + XLogRecData rdata; + + rdata.data = (char *) (&nextOid); + rdata.len = sizeof(Oid); + rdata.buffer = InvalidBuffer; + rdata.next = NULL; + (void) XLogInsert(RM_XLOG_ID, XLOG_NEXTOID, &rdata); + + /* + * We need not flush the NEXTOID record immediately, because any of the + * just-allocated OIDs could only reach disk as part of a tuple insert or + * update that would have its own XLOG record that must follow the NEXTOID + * record. Therefore, the standard buffer LSN interlock applied to those + * records will ensure no such OID reaches disk before the NEXTOID record + * does. + * + * Note, however, that the above statement only covers state "within" the + * database. When we use a generated OID as a file or directory name, we + * are in a sense violating the basic WAL rule, because that filesystem + * change may reach disk before the NEXTOID WAL record does. The impact + * of this is that if a database crash occurs immediately afterward, we + * might after restart re-generate the same OID and find that it conflicts + * with the leftover file or directory. But since for safety's sake we + * always loop until finding a nonconflicting filename, this poses no real + * problem in practice. See pgsql-hackers discussion 27-Sep-2006. + */ + } + + /* + * Write an XLOG SWITCH record. + * + * Here we just blindly issue an XLogInsert request for the record. + * All the magic happens inside XLogInsert. + * + * The return value is either the end+1 address of the switch record, + * or the end+1 address of the prior segment if we did not need to + * write a switch record because we are already at segment start. + */ + XLogRecPtr + RequestXLogSwitch(void) + { + XLogRecPtr RecPtr; + XLogRecData rdata; + + /* XLOG SWITCH, alone among xlog record types, has no data */ + rdata.buffer = InvalidBuffer; + rdata.data = NULL; + rdata.len = 0; + rdata.next = NULL; + + RecPtr = XLogInsert(RM_XLOG_ID, XLOG_SWITCH, &rdata); + + return RecPtr; + } + + /* + * XLOG resource manager's routines + */ + void + xlog_redo(XLogRecPtr lsn, XLogRecord *record) + { + uint8 info = record->xl_info & ~XLR_INFO_MASK; + + /* Backup blocks are not used in xlog records */ + Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK)); + + if (info == XLOG_NEXTOID) + { + Oid nextOid; + + memcpy(&nextOid, XLogRecGetData(record), sizeof(Oid)); + if (ShmemVariableCache->nextOid < nextOid) + { + ShmemVariableCache->nextOid = nextOid; + ShmemVariableCache->oidCount = 0; + } + } + else if (info == XLOG_CHECKPOINT_SHUTDOWN) + { + CheckPoint checkPoint; + + memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint)); + /* In a SHUTDOWN checkpoint, believe the counters exactly */ + ShmemVariableCache->nextXid = checkPoint.nextXid; + ShmemVariableCache->nextOid = checkPoint.nextOid; + ShmemVariableCache->oidCount = 0; + MultiXactSetNextMXact(checkPoint.nextMulti, + checkPoint.nextMultiOffset); + + /* ControlFile->checkPointCopy always tracks the latest ckpt XID */ + ControlFile->checkPointCopy.nextXidEpoch = checkPoint.nextXidEpoch; + ControlFile->checkPointCopy.nextXid = checkPoint.nextXid; + + /* + * TLI may change in a shutdown checkpoint, but it shouldn't decrease + */ + if (checkPoint.ThisTimeLineID != ThisTimeLineID) + { + if (checkPoint.ThisTimeLineID < ThisTimeLineID || + !list_member_int(expectedTLIs, + (int) checkPoint.ThisTimeLineID)) + ereport(PANIC, + (errmsg("unexpected timeline ID %u (after %u) in checkpoint record", + checkPoint.ThisTimeLineID, ThisTimeLineID))); + /* Following WAL records should be run with new TLI */ + ThisTimeLineID = checkPoint.ThisTimeLineID; + } + + RecoveryRestartPoint(&checkPoint); + } + else if (info == XLOG_CHECKPOINT_ONLINE) + { + CheckPoint checkPoint; + + memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint)); + /* In an ONLINE checkpoint, treat the counters like NEXTOID */ + if (TransactionIdPrecedes(ShmemVariableCache->nextXid, + checkPoint.nextXid)) + ShmemVariableCache->nextXid = checkPoint.nextXid; + if (ShmemVariableCache->nextOid < checkPoint.nextOid) + { + ShmemVariableCache->nextOid = checkPoint.nextOid; + ShmemVariableCache->oidCount = 0; + } + MultiXactAdvanceNextMXact(checkPoint.nextMulti, + checkPoint.nextMultiOffset); + + /* ControlFile->checkPointCopy always tracks the latest ckpt XID */ + ControlFile->checkPointCopy.nextXidEpoch = checkPoint.nextXidEpoch; + ControlFile->checkPointCopy.nextXid = checkPoint.nextXid; + + /* TLI should not change in an on-line checkpoint */ + if (checkPoint.ThisTimeLineID != ThisTimeLineID) + ereport(PANIC, + (errmsg("unexpected timeline ID %u (should be %u) in checkpoint record", + checkPoint.ThisTimeLineID, ThisTimeLineID))); + + RecoveryRestartPoint(&checkPoint); + } + else if (info == XLOG_NOOP) + { + /* nothing to do here */ + } + else if (info == XLOG_SWITCH) + { + /* nothing to do here */ + } + } + + void + xlog_desc(StringInfo buf, uint8 xl_info, char *rec) + { + uint8 info = xl_info & ~XLR_INFO_MASK; + + if (info == XLOG_CHECKPOINT_SHUTDOWN || + info == XLOG_CHECKPOINT_ONLINE) + { + CheckPoint *checkpoint = (CheckPoint *) rec; + + appendStringInfo(buf, "checkpoint: redo %X/%X; " + "tli %u; xid %u/%u; oid %u; multi %u; offset %u; %s", + checkpoint->redo.xlogid, checkpoint->redo.xrecoff, + checkpoint->ThisTimeLineID, + checkpoint->nextXidEpoch, checkpoint->nextXid, + checkpoint->nextOid, + checkpoint->nextMulti, + checkpoint->nextMultiOffset, + (info == XLOG_CHECKPOINT_SHUTDOWN) ? "shutdown" : "online"); + } + else if (info == XLOG_NOOP) + { + appendStringInfo(buf, "xlog no-op"); + } + else if (info == XLOG_NEXTOID) + { + Oid nextOid; + + memcpy(&nextOid, rec, sizeof(Oid)); + appendStringInfo(buf, "nextOid: %u", nextOid); + } + else if (info == XLOG_SWITCH) + { + appendStringInfo(buf, "xlog switch"); + } + else + appendStringInfo(buf, "UNKNOWN"); + } + + #ifdef WAL_DEBUG + + static void + xlog_outrec(StringInfo buf, XLogRecord *record) + { + int i; + + appendStringInfo(buf, "prev %X/%X; xid %u", + record->xl_prev.xlogid, record->xl_prev.xrecoff, + record->xl_xid); + + for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++) + { + if (record->xl_info & XLR_SET_BKP_BLOCK(i)) + appendStringInfo(buf, "; bkpb%d", i + 1); + } + + appendStringInfo(buf, ": %s", RmgrTable[record->xl_rmid].rm_name); + } + #endif /* WAL_DEBUG */ + + + /* + * Return the (possible) sync flag used for opening a file, depending on the + * value of the GUC wal_sync_method. + */ + static int + get_sync_bit(int method) + { + /* If fsync is disabled, never open in sync mode */ + if (!enableFsync) + return 0; + + switch (method) + { + /* + * enum values for all sync options are defined even if they are not + * supported on the current platform. But if not, they are not + * included in the enum option array, and therefore will never be seen + * here. + */ + case SYNC_METHOD_FSYNC: + case SYNC_METHOD_FSYNC_WRITETHROUGH: + case SYNC_METHOD_FDATASYNC: + return 0; + #ifdef OPEN_SYNC_FLAG + case SYNC_METHOD_OPEN: + return OPEN_SYNC_FLAG; + #endif + #ifdef OPEN_DATASYNC_FLAG + case SYNC_METHOD_OPEN_DSYNC: + return OPEN_DATASYNC_FLAG; + #endif + default: + /* can't happen (unless we are out of sync with option array) */ + elog(ERROR, "unrecognized wal_sync_method: %d", method); + return 0; /* silence warning */ + } + } + + /* + * GUC support + */ + bool + assign_xlog_sync_method(int new_sync_method, bool doit, GucSource source) + { + if (!doit) + return true; + + if (sync_method != new_sync_method) + { + /* + * To ensure that no blocks escape unsynced, force an fsync on the + * currently open log segment (if any). Also, if the open flag is + * changing, close the log file so it will be reopened (with new flag + * bit) at next use. + */ + if (openLogFile >= 0) + { + if (pg_fsync(openLogFile) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync log file %u, segment %u: %m", + openLogId, openLogSeg))); + if (get_sync_bit(sync_method) != get_sync_bit(new_sync_method)) + XLogFileClose(); + } + } + + return true; + } + + + /* + * Issue appropriate kind of fsync (if any) on the current XLOG output file + */ + static void + issue_xlog_fsync(void) + { + switch (sync_method) + { + case SYNC_METHOD_FSYNC: + if (pg_fsync_no_writethrough(openLogFile) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync log file %u, segment %u: %m", + openLogId, openLogSeg))); + break; + #ifdef HAVE_FSYNC_WRITETHROUGH + case SYNC_METHOD_FSYNC_WRITETHROUGH: + if (pg_fsync_writethrough(openLogFile) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fsync write-through log file %u, segment %u: %m", + openLogId, openLogSeg))); + break; + #endif + #ifdef HAVE_FDATASYNC + case SYNC_METHOD_FDATASYNC: + if (pg_fdatasync(openLogFile) != 0) + ereport(PANIC, + (errcode_for_file_access(), + errmsg("could not fdatasync log file %u, segment %u: %m", + openLogId, openLogSeg))); + break; + #endif + case SYNC_METHOD_OPEN: + case SYNC_METHOD_OPEN_DSYNC: + /* write synced it already */ + break; + default: + elog(PANIC, "unrecognized wal_sync_method: %d", sync_method); + break; + } + } + + + /* + * pg_start_backup: set up for taking an on-line backup dump + * + * Essentially what this does is to create a backup label file in $PGDATA, + * where it will be archived as part of the backup dump. The label file + * contains the user-supplied label string (typically this would be used + * to tell where the backup dump will be stored) and the starting time and + * starting WAL location for the dump. + */ + Datum + pg_start_backup(PG_FUNCTION_ARGS) + { + text *backupid = PG_GETARG_TEXT_P(0); + char *backupidstr; + XLogRecPtr checkpointloc; + XLogRecPtr startpoint; + pg_time_t stamp_time; + char strfbuf[128]; + char xlogfilename[MAXFNAMELEN]; + uint32 _logId; + uint32 _logSeg; + struct stat stat_buf; + FILE *fp; + + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("must be superuser to run a backup"))); + + if (!XLogArchivingActive()) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("WAL archiving is not active"), + errhint("archive_mode must be enabled at server start."))); + + if (!XLogArchiveCommandSet()) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("WAL archiving is not active"), + errhint("archive_command must be defined before " + "online backups can be made safely."))); + + backupidstr = text_to_cstring(backupid); + + /* + * Mark backup active in shared memory. We must do full-page WAL writes + * during an on-line backup even if not doing so at other times, because + * it's quite possible for the backup dump to obtain a "torn" (partially + * written) copy of a database page if it reads the page concurrently with + * our write to the same page. This can be fixed as long as the first + * write to the page in the WAL sequence is a full-page write. Hence, we + * turn on forcePageWrites and then force a CHECKPOINT, to ensure there + * are no dirty pages in shared memory that might get dumped while the + * backup is in progress without having a corresponding WAL record. (Once + * the backup is complete, we need not force full-page writes anymore, + * since we expect that any pages not modified during the backup interval + * must have been correctly captured by the backup.) + * + * We must hold WALInsertLock to change the value of forcePageWrites, to + * ensure adequate interlocking against XLogInsert(). + */ + LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); + if (XLogCtl->Insert.forcePageWrites) + { + LWLockRelease(WALInsertLock); + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("a backup is already in progress"), + errhint("Run pg_stop_backup() and try again."))); + } + XLogCtl->Insert.forcePageWrites = true; + LWLockRelease(WALInsertLock); + + /* Ensure we release forcePageWrites if fail below */ + PG_ENSURE_ERROR_CLEANUP(pg_start_backup_callback, (Datum) 0); + { + /* + * Force a CHECKPOINT. Aside from being necessary to prevent torn + * page problems, this guarantees that two successive backup runs will + * have different checkpoint positions and hence different history + * file names, even if nothing happened in between. + * + * We don't use CHECKPOINT_IMMEDIATE, hence this can take awhile. + */ + RequestCheckpoint(CHECKPOINT_FORCE | CHECKPOINT_WAIT); + + /* + * Now we need to fetch the checkpoint record location, and also its + * REDO pointer. The oldest point in WAL that would be needed to + * restore starting from the checkpoint is precisely the REDO pointer. + */ + LWLockAcquire(ControlFileLock, LW_EXCLUSIVE); + checkpointloc = ControlFile->checkPoint; + startpoint = ControlFile->checkPointCopy.redo; + LWLockRelease(ControlFileLock); + + XLByteToSeg(startpoint, _logId, _logSeg); + XLogFileName(xlogfilename, ThisTimeLineID, _logId, _logSeg); + + /* Use the log timezone here, not the session timezone */ + stamp_time = (pg_time_t) time(NULL); + pg_strftime(strfbuf, sizeof(strfbuf), + "%Y-%m-%d %H:%M:%S %Z", + pg_localtime(&stamp_time, log_timezone)); + + /* + * Check for existing backup label --- implies a backup is already + * running. (XXX given that we checked forcePageWrites above, maybe + * it would be OK to just unlink any such label file?) + */ + if (stat(BACKUP_LABEL_FILE, &stat_buf) != 0) + { + if (errno != ENOENT) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not stat file \"%s\": %m", + BACKUP_LABEL_FILE))); + } + else + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("a backup is already in progress"), + errhint("If you're sure there is no backup in progress, remove file \"%s\" and try again.", + BACKUP_LABEL_FILE))); + + /* + * Okay, write the file + */ + fp = AllocateFile(BACKUP_LABEL_FILE, "w"); + if (!fp) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not create file \"%s\": %m", + BACKUP_LABEL_FILE))); + fprintf(fp, "START WAL LOCATION: %X/%X (file %s)\n", + startpoint.xlogid, startpoint.xrecoff, xlogfilename); + fprintf(fp, "CHECKPOINT LOCATION: %X/%X\n", + checkpointloc.xlogid, checkpointloc.xrecoff); + fprintf(fp, "START TIME: %s\n", strfbuf); + fprintf(fp, "LABEL: %s\n", backupidstr); + if (fflush(fp) || ferror(fp) || FreeFile(fp)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write file \"%s\": %m", + BACKUP_LABEL_FILE))); + } + PG_END_ENSURE_ERROR_CLEANUP(pg_start_backup_callback, (Datum) 0); + + /* + * We're done. As a convenience, return the starting WAL location. + */ + snprintf(xlogfilename, sizeof(xlogfilename), "%X/%X", + startpoint.xlogid, startpoint.xrecoff); + PG_RETURN_TEXT_P(cstring_to_text(xlogfilename)); + } + + /* Error cleanup callback for pg_start_backup */ + static void + pg_start_backup_callback(int code, Datum arg) + { + /* Turn off forcePageWrites on failure */ + LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); + XLogCtl->Insert.forcePageWrites = false; + LWLockRelease(WALInsertLock); + } + + /* + * pg_stop_backup: finish taking an on-line backup dump + * + * We remove the backup label file created by pg_start_backup, and instead + * create a backup history file in pg_xlog (whence it will immediately be + * archived). The backup history file contains the same info found in + * the label file, plus the backup-end time and WAL location. + * Note: different from CancelBackup which just cancels online backup mode. + */ + Datum + pg_stop_backup(PG_FUNCTION_ARGS) + { + XLogRecPtr startpoint; + XLogRecPtr stoppoint; + pg_time_t stamp_time; + char strfbuf[128]; + char histfilepath[MAXPGPATH]; + char startxlogfilename[MAXFNAMELEN]; + char stopxlogfilename[MAXFNAMELEN]; + char lastxlogfilename[MAXFNAMELEN]; + char histfilename[MAXFNAMELEN]; + uint32 _logId; + uint32 _logSeg; + FILE *lfp; + FILE *fp; + char ch; + int ich; + int seconds_before_warning; + int waits = 0; + + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + (errmsg("must be superuser to run a backup")))); + + if (!XLogArchivingActive()) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("WAL archiving is not active"), + errhint("archive_mode must be enabled at server start."))); + + /* + * OK to clear forcePageWrites + */ + LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); + XLogCtl->Insert.forcePageWrites = false; + LWLockRelease(WALInsertLock); + + /* + * Force a switch to a new xlog segment file, so that the backup is valid + * as soon as archiver moves out the current segment file. We'll report + * the end address of the XLOG SWITCH record as the backup stopping point. + */ + stoppoint = RequestXLogSwitch(); + + XLByteToSeg(stoppoint, _logId, _logSeg); + XLogFileName(stopxlogfilename, ThisTimeLineID, _logId, _logSeg); + + /* Use the log timezone here, not the session timezone */ + stamp_time = (pg_time_t) time(NULL); + pg_strftime(strfbuf, sizeof(strfbuf), + "%Y-%m-%d %H:%M:%S %Z", + pg_localtime(&stamp_time, log_timezone)); + + /* + * Open the existing label file + */ + lfp = AllocateFile(BACKUP_LABEL_FILE, "r"); + if (!lfp) + { + if (errno != ENOENT) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", + BACKUP_LABEL_FILE))); + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("a backup is not in progress"))); + } + + /* + * Read and parse the START WAL LOCATION line (this code is pretty crude, + * but we are not expecting any variability in the file format). + */ + if (fscanf(lfp, "START WAL LOCATION: %X/%X (file %24s)%c", + &startpoint.xlogid, &startpoint.xrecoff, startxlogfilename, + &ch) != 4 || ch != '\n') + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE))); + + /* + * Write the backup history file + */ + XLByteToSeg(startpoint, _logId, _logSeg); + BackupHistoryFilePath(histfilepath, ThisTimeLineID, _logId, _logSeg, + startpoint.xrecoff % XLogSegSize); + fp = AllocateFile(histfilepath, "w"); + if (!fp) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not create file \"%s\": %m", + histfilepath))); + fprintf(fp, "START WAL LOCATION: %X/%X (file %s)\n", + startpoint.xlogid, startpoint.xrecoff, startxlogfilename); + fprintf(fp, "STOP WAL LOCATION: %X/%X (file %s)\n", + stoppoint.xlogid, stoppoint.xrecoff, stopxlogfilename); + /* transfer remaining lines from label to history file */ + while ((ich = fgetc(lfp)) != EOF) + fputc(ich, fp); + fprintf(fp, "STOP TIME: %s\n", strfbuf); + if (fflush(fp) || ferror(fp) || FreeFile(fp)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write file \"%s\": %m", + histfilepath))); + + /* + * Close and remove the backup label file + */ + if (ferror(lfp) || FreeFile(lfp)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", + BACKUP_LABEL_FILE))); + if (unlink(BACKUP_LABEL_FILE) != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not remove file \"%s\": %m", + BACKUP_LABEL_FILE))); + + /* + * Clean out any no-longer-needed history files. As a side effect, this + * will post a .ready file for the newly created history file, notifying + * the archiver that history file may be archived immediately. + */ + CleanupBackupHistory(); + + /* + * Wait until both the last WAL file filled during backup and the history + * file have been archived. We assume that the alphabetic sorting + * property of the WAL files ensures any earlier WAL files are safely + * archived as well. + * + * We wait forever, since archive_command is supposed to work and + * we assume the admin wanted his backup to work completely. If you + * don't wish to wait, you can set statement_timeout. + */ + XLByteToPrevSeg(stoppoint, _logId, _logSeg); + XLogFileName(lastxlogfilename, ThisTimeLineID, _logId, _logSeg); + + XLByteToSeg(startpoint, _logId, _logSeg); + BackupHistoryFileName(histfilename, ThisTimeLineID, _logId, _logSeg, + startpoint.xrecoff % XLogSegSize); + + seconds_before_warning = 60; + waits = 0; + + while (XLogArchiveIsBusy(lastxlogfilename) || + XLogArchiveIsBusy(histfilename)) + { + CHECK_FOR_INTERRUPTS(); + + pg_usleep(1000000L); + + if (++waits >= seconds_before_warning) + { + seconds_before_warning *= 2; /* This wraps in >10 years... */ + ereport(WARNING, + (errmsg("pg_stop_backup still waiting for archive to complete (%d seconds elapsed)", + waits))); + } + } + + /* + * We're done. As a convenience, return the ending WAL location. + */ + snprintf(stopxlogfilename, sizeof(stopxlogfilename), "%X/%X", + stoppoint.xlogid, stoppoint.xrecoff); + PG_RETURN_TEXT_P(cstring_to_text(stopxlogfilename)); + } + + /* + * pg_switch_xlog: switch to next xlog file + */ + Datum + pg_switch_xlog(PG_FUNCTION_ARGS) + { + XLogRecPtr switchpoint; + char location[MAXFNAMELEN]; + + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + (errmsg("must be superuser to switch transaction log files")))); + + switchpoint = RequestXLogSwitch(); + + /* + * As a convenience, return the WAL location of the switch record + */ + snprintf(location, sizeof(location), "%X/%X", + switchpoint.xlogid, switchpoint.xrecoff); + PG_RETURN_TEXT_P(cstring_to_text(location)); + } + + /* + * Report the current WAL write location (same format as pg_start_backup etc) + * + * This is useful for determining how much of WAL is visible to an external + * archiving process. Note that the data before this point is written out + * to the kernel, but is not necessarily synced to disk. + */ + Datum + pg_current_xlog_location(PG_FUNCTION_ARGS) + { + char location[MAXFNAMELEN]; + + /* Make sure we have an up-to-date local LogwrtResult */ + { + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + + SpinLockAcquire(&xlogctl->info_lck); + LogwrtResult = xlogctl->LogwrtResult; + SpinLockRelease(&xlogctl->info_lck); + } + + snprintf(location, sizeof(location), "%X/%X", + LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff); + PG_RETURN_TEXT_P(cstring_to_text(location)); + } + + /* + * Report the current WAL insert location (same format as pg_start_backup etc) + * + * This function is mostly for debugging purposes. + */ + Datum + pg_current_xlog_insert_location(PG_FUNCTION_ARGS) + { + XLogCtlInsert *Insert = &XLogCtl->Insert; + XLogRecPtr current_recptr; + char location[MAXFNAMELEN]; + + /* + * Get the current end-of-WAL position ... shared lock is sufficient + */ + LWLockAcquire(WALInsertLock, LW_SHARED); + INSERT_RECPTR(current_recptr, Insert, Insert->curridx); + LWLockRelease(WALInsertLock); + + snprintf(location, sizeof(location), "%X/%X", + current_recptr.xlogid, current_recptr.xrecoff); + PG_RETURN_TEXT_P(cstring_to_text(location)); + } + + /* + * Compute an xlog file name and decimal byte offset given a WAL location, + * such as is returned by pg_stop_backup() or pg_xlog_switch(). + * + * Note that a location exactly at a segment boundary is taken to be in + * the previous segment. This is usually the right thing, since the + * expected usage is to determine which xlog file(s) are ready to archive. + */ + Datum + pg_xlogfile_name_offset(PG_FUNCTION_ARGS) + { + text *location = PG_GETARG_TEXT_P(0); + char *locationstr; + unsigned int uxlogid; + unsigned int uxrecoff; + uint32 xlogid; + uint32 xlogseg; + uint32 xrecoff; + XLogRecPtr locationpoint; + char xlogfilename[MAXFNAMELEN]; + Datum values[2]; + bool isnull[2]; + TupleDesc resultTupleDesc; + HeapTuple resultHeapTuple; + Datum result; + + /* + * Read input and parse + */ + locationstr = text_to_cstring(location); + + if (sscanf(locationstr, "%X/%X", &uxlogid, &uxrecoff) != 2) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("could not parse transaction log location \"%s\"", + locationstr))); + + locationpoint.xlogid = uxlogid; + locationpoint.xrecoff = uxrecoff; + + /* + * Construct a tuple descriptor for the result row. This must match this + * function's pg_proc entry! + */ + resultTupleDesc = CreateTemplateTupleDesc(2, false); + TupleDescInitEntry(resultTupleDesc, (AttrNumber) 1, "file_name", + TEXTOID, -1, 0); + TupleDescInitEntry(resultTupleDesc, (AttrNumber) 2, "file_offset", + INT4OID, -1, 0); + + resultTupleDesc = BlessTupleDesc(resultTupleDesc); + + /* + * xlogfilename + */ + XLByteToPrevSeg(locationpoint, xlogid, xlogseg); + XLogFileName(xlogfilename, ThisTimeLineID, xlogid, xlogseg); + + values[0] = CStringGetTextDatum(xlogfilename); + isnull[0] = false; + + /* + * offset + */ + xrecoff = locationpoint.xrecoff - xlogseg * XLogSegSize; + + values[1] = UInt32GetDatum(xrecoff); + isnull[1] = false; + + /* + * Tuple jam: Having first prepared your Datums, then squash together + */ + resultHeapTuple = heap_form_tuple(resultTupleDesc, values, isnull); + + result = HeapTupleGetDatum(resultHeapTuple); + + PG_RETURN_DATUM(result); + } + + /* + * Compute an xlog file name given a WAL location, + * such as is returned by pg_stop_backup() or pg_xlog_switch(). + */ + Datum + pg_xlogfile_name(PG_FUNCTION_ARGS) + { + text *location = PG_GETARG_TEXT_P(0); + char *locationstr; + unsigned int uxlogid; + unsigned int uxrecoff; + uint32 xlogid; + uint32 xlogseg; + XLogRecPtr locationpoint; + char xlogfilename[MAXFNAMELEN]; + + locationstr = text_to_cstring(location); + + if (sscanf(locationstr, "%X/%X", &uxlogid, &uxrecoff) != 2) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("could not parse transaction log location \"%s\"", + locationstr))); + + locationpoint.xlogid = uxlogid; + locationpoint.xrecoff = uxrecoff; + + XLByteToPrevSeg(locationpoint, xlogid, xlogseg); + XLogFileName(xlogfilename, ThisTimeLineID, xlogid, xlogseg); + + PG_RETURN_TEXT_P(cstring_to_text(xlogfilename)); + } + + /* + * read_backup_label: check to see if a backup_label file is present + * + * If we see a backup_label during recovery, we assume that we are recovering + * from a backup dump file, and we therefore roll forward from the checkpoint + * identified by the label file, NOT what pg_control says. This avoids the + * problem that pg_control might have been archived one or more checkpoints + * later than the start of the dump, and so if we rely on it as the start + * point, we will fail to restore a consistent database state. + * + * We also attempt to retrieve the corresponding backup history file. + * If successful, set *minRecoveryLoc to constrain valid PITR stopping + * points. + * + * Returns TRUE if a backup_label was found (and fills the checkpoint + * location into *checkPointLoc); returns FALSE if not. + */ + static bool + read_backup_label(XLogRecPtr *checkPointLoc, XLogRecPtr *minRecoveryLoc) + { + XLogRecPtr startpoint; + XLogRecPtr stoppoint; + char histfilename[MAXFNAMELEN]; + char histfilepath[MAXPGPATH]; + char startxlogfilename[MAXFNAMELEN]; + char stopxlogfilename[MAXFNAMELEN]; + TimeLineID tli; + uint32 _logId; + uint32 _logSeg; + FILE *lfp; + FILE *fp; + char ch; + + /* Default is to not constrain recovery stop point */ + minRecoveryLoc->xlogid = 0; + minRecoveryLoc->xrecoff = 0; + + /* + * See if label file is present + */ + lfp = AllocateFile(BACKUP_LABEL_FILE, "r"); + if (!lfp) + { + if (errno != ENOENT) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", + BACKUP_LABEL_FILE))); + return false; /* it's not there, all is fine */ + } + + /* + * Read and parse the START WAL LOCATION and CHECKPOINT lines (this code + * is pretty crude, but we are not expecting any variability in the file + * format). + */ + if (fscanf(lfp, "START WAL LOCATION: %X/%X (file %08X%16s)%c", + &startpoint.xlogid, &startpoint.xrecoff, &tli, + startxlogfilename, &ch) != 5 || ch != '\n') + ereport(FATAL, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE))); + if (fscanf(lfp, "CHECKPOINT LOCATION: %X/%X%c", + &checkPointLoc->xlogid, &checkPointLoc->xrecoff, + &ch) != 3 || ch != '\n') + ereport(FATAL, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE))); + if (ferror(lfp) || FreeFile(lfp)) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", + BACKUP_LABEL_FILE))); + + /* + * Try to retrieve the backup history file (no error if we can't) + */ + XLByteToSeg(startpoint, _logId, _logSeg); + BackupHistoryFileName(histfilename, tli, _logId, _logSeg, + startpoint.xrecoff % XLogSegSize); + + if (InArchiveRecovery) + RestoreArchivedFile(histfilepath, histfilename, "RECOVERYHISTORY", 0); + else + BackupHistoryFilePath(histfilepath, tli, _logId, _logSeg, + startpoint.xrecoff % XLogSegSize); + + fp = AllocateFile(histfilepath, "r"); + if (fp) + { + /* + * Parse history file to identify stop point. + */ + if (fscanf(fp, "START WAL LOCATION: %X/%X (file %24s)%c", + &startpoint.xlogid, &startpoint.xrecoff, startxlogfilename, + &ch) != 4 || ch != '\n') + ereport(FATAL, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("invalid data in file \"%s\"", histfilename))); + if (fscanf(fp, "STOP WAL LOCATION: %X/%X (file %24s)%c", + &stoppoint.xlogid, &stoppoint.xrecoff, stopxlogfilename, + &ch) != 4 || ch != '\n') + ereport(FATAL, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("invalid data in file \"%s\"", histfilename))); + *minRecoveryLoc = stoppoint; + if (ferror(fp) || FreeFile(fp)) + ereport(FATAL, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", + histfilepath))); + } + + return true; + } + + /* + * Error context callback for errors occurring during rm_redo(). + */ + static void + rm_redo_error_callback(void *arg) + { + XLogRecord *record = (XLogRecord *) arg; + StringInfoData buf; + + initStringInfo(&buf); + RmgrTable[record->xl_rmid].rm_desc(&buf, + record->xl_info, + XLogRecGetData(record)); + + /* don't bother emitting empty description */ + if (buf.len > 0) + errcontext("xlog redo %s", buf.data); + + pfree(buf.data); + } + + /* + * BackupInProgress: check if online backup mode is active + * + * This is done by checking for existence of the "backup_label" file. + */ + bool + BackupInProgress(void) + { + struct stat stat_buf; + + return (stat(BACKUP_LABEL_FILE, &stat_buf) == 0); + } + + /* + * CancelBackup: rename the "backup_label" file to cancel backup mode + * + * If the "backup_label" file exists, it will be renamed to "backup_label.old". + * Note that this will render an online backup in progress useless. + * To correctly finish an online backup, pg_stop_backup must be called. + */ + void + CancelBackup(void) + { + struct stat stat_buf; + + /* if the file is not there, return */ + if (stat(BACKUP_LABEL_FILE, &stat_buf) < 0) + return; + + /* remove leftover file from previously cancelled backup if it exists */ + unlink(BACKUP_LABEL_OLD); + + if (rename(BACKUP_LABEL_FILE, BACKUP_LABEL_OLD) == 0) + { + ereport(LOG, + (errmsg("online backup mode cancelled"), + errdetail("\"%s\" was renamed to \"%s\".", + BACKUP_LABEL_FILE, BACKUP_LABEL_OLD))); + } + else + { + ereport(WARNING, + (errcode_for_file_access(), + errmsg("online backup mode was not cancelled"), + errdetail("Could not rename \"%s\" to \"%s\": %m.", + BACKUP_LABEL_FILE, BACKUP_LABEL_OLD))); + } + } + diff -rcN Postgresql-CVS-20090313.org/src/backend/commands/sequence.c Postgresql-CVS-20090313/src/backend/commands/sequence.c *** Postgresql-CVS-20090313.org/src/backend/commands/sequence.c 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/commands/sequence.c 2009-03-13 16:37:09.000000000 +0900 *************** *** 17,22 **** --- 17,23 ---- #include "access/heapam.h" #include "access/transam.h" #include "access/xact.h" + #include "access/xlog.h" #include "access/xlogutils.h" #include "catalog/dependency.h" #include "catalog/namespace.h" *************** *** 1385,1387 **** --- 1386,1418 ---- appendStringInfo(buf, "rel %u/%u/%u", xlrec->node.spcNode, xlrec->node.dbNode, xlrec->node.relNode); } + + /* + * seq_readahead - enqueue information about data pages + * + * The readahead module stores information about pages that are modified through + * redo-ing record. + * + */ + bool + seq_readahead(XLogRecPtr lsn, XLogRecord *record) + { + uint8 info = record->xl_info & ~XLR_INFO_MASK; + + Assert(record); + + switch (info) + { + case XLOG_SEQ_LOG: + { + xl_seq_rec *xlrec = (xl_seq_rec *) XLogRecGetData(record); + + if (!ReadAheadHasRoom(1)) + return false; + ReadAheadAddEntry(xlrec->node, 0, lsn.xrecoff, false); + break; + } + } + + return true; + } diff -rcN Postgresql-CVS-20090313.org/src/backend/storage/smgr/md.c Postgresql-CVS-20090313/src/backend/storage/smgr/md.c *** Postgresql-CVS-20090313.org/src/backend/storage/smgr/md.c 2009-03-13 14:23:02.000000000 +0900 --- Postgresql-CVS-20090313/src/backend/storage/smgr/md.c 2009-03-13 16:37:09.000000000 +0900 *************** *** 560,566 **** off_t seekpos; MdfdVec *v; ! v = _mdfd_getseg(reln, forknum, blocknum, false, EXTENSION_FAIL); seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE)); Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE); --- 560,568 ---- off_t seekpos; MdfdVec *v; ! v = _mdfd_getseg(reln, forknum, blocknum, false, EXTENSION_RETURN_NULL); ! if (!v) ! return; seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE)); Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE); diff -rcN Postgresql-CVS-20090313.org/src/include/access/gin.h Postgresql-CVS-20090313/src/include/access/gin.h *** Postgresql-CVS-20090313.org/src/include/access/gin.h 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/include/access/gin.h 2009-03-13 16:37:09.000000000 +0900 *************** *** 256,261 **** --- 256,262 ---- /* ginxlog.c */ extern void gin_redo(XLogRecPtr lsn, XLogRecord *record); extern void gin_desc(StringInfo buf, uint8 xl_info, char *rec); + extern bool gin_readahead(XLogRecPtr lsn, XLogRecord *record); extern void gin_xlog_startup(void); extern void gin_xlog_cleanup(void); extern bool gin_safe_restartpoint(void); diff -rcN Postgresql-CVS-20090313.org/src/include/access/gist_private.h Postgresql-CVS-20090313/src/include/access/gist_private.h *** Postgresql-CVS-20090313.org/src/include/access/gist_private.h 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/include/access/gist_private.h 2009-03-13 16:37:09.000000000 +0900 *************** *** 250,255 **** --- 250,256 ---- /* gistxlog.c */ extern void gist_redo(XLogRecPtr lsn, XLogRecord *record); extern void gist_desc(StringInfo buf, uint8 xl_info, char *rec); + extern bool gist_readahead(XLogRecPtr lsn, XLogRecord *record); extern void gist_xlog_startup(void); extern void gist_xlog_cleanup(void); extern bool gist_safe_restartpoint(void); diff -rcN Postgresql-CVS-20090313.org/src/include/access/heapam.h Postgresql-CVS-20090313/src/include/access/heapam.h *** Postgresql-CVS-20090313.org/src/include/access/heapam.h 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/include/access/heapam.h 2009-03-13 16:37:09.000000000 +0900 *************** *** 124,131 **** --- 124,133 ---- extern void heap_redo(XLogRecPtr lsn, XLogRecord *rptr); extern void heap_desc(StringInfo buf, uint8 xl_info, char *rec); + extern bool heap_readahead(XLogRecPtr lsn, XLogRecord *rptr); extern void heap2_redo(XLogRecPtr lsn, XLogRecord *rptr); extern void heap2_desc(StringInfo buf, uint8 xl_info, char *rec); + extern bool heap2_readahead(XLogRecPtr lsn, XLogRecord *rptr); extern XLogRecPtr log_heap_move(Relation reln, Buffer oldbuf, ItemPointerData from, diff -rcN Postgresql-CVS-20090313.org/src/include/access/nbtree.h Postgresql-CVS-20090313/src/include/access/nbtree.h *** Postgresql-CVS-20090313.org/src/include/access/nbtree.h 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/include/access/nbtree.h 2009-03-13 16:37:09.000000000 +0900 *************** *** 591,596 **** --- 591,597 ---- */ extern void btree_redo(XLogRecPtr lsn, XLogRecord *record); extern void btree_desc(StringInfo buf, uint8 xl_info, char *rec); + extern bool btree_readahead(XLogRecPtr lns, XLogRecord *rptr); extern void btree_xlog_startup(void); extern void btree_xlog_cleanup(void); extern bool btree_safe_restartpoint(void); diff -rcN Postgresql-CVS-20090313.org/src/include/access/xlog.h Postgresql-CVS-20090313/src/include/access/xlog.h *** Postgresql-CVS-20090313.org/src/include/access/xlog.h 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/include/access/xlog.h 2009-03-13 16:37:09.000000000 +0900 *************** *** 14,20 **** --- 14,23 ---- #include "access/rmgr.h" #include "access/xlogdefs.h" #include "lib/stringinfo.h" + #include "postgres.h" #include "storage/buf.h" + #include "storage/relfilenode.h" + #include "storage/block.h" #include "utils/pg_crc.h" #include "utils/timestamp.h" *************** *** 198,203 **** --- 201,207 ---- extern void xlog_redo(XLogRecPtr lsn, XLogRecord *record); extern void xlog_desc(StringInfo buf, uint8 xl_info, char *rec); + extern bool xlog_readahead(XLogRecPtr lsn, XLogRecord *rptr); extern void UpdateControlFile(void); extern Size XLOGShmemSize(void); *************** *** 212,215 **** --- 216,227 ---- extern XLogRecPtr GetInsertRecPtr(void); extern void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch); + /* Implimented in readahead.c. */ + extern void ReadAheadInit(void); + extern void ReadAheadAddEntry(RelFileNode node, BlockNumber blkno, + uint32 xrecoff, bool has_fpw); + extern bool ReadAheadHasRoom(int num); + extern void ReadAheadExecute(void); + extern void ReadAheadFinish(void); + #endif /* XLOG_H */ diff -rcN Postgresql-CVS-20090313.org/src/include/access/xlog.h.orig Postgresql-CVS-20090313/src/include/access/xlog.h.orig *** Postgresql-CVS-20090313.org/src/include/access/xlog.h.orig 1970-01-01 09:00:00.000000000 +0900 --- Postgresql-CVS-20090313/src/include/access/xlog.h.orig 2009-03-13 04:02:58.000000000 +0900 *************** *** 0 **** --- 1,215 ---- + /* + * xlog.h + * + * PostgreSQL transaction log manager + * + * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.90 2009/01/20 18:59:37 heikki Exp $ + */ + #ifndef XLOG_H + #define XLOG_H + + #include "access/rmgr.h" + #include "access/xlogdefs.h" + #include "lib/stringinfo.h" + #include "storage/buf.h" + #include "utils/pg_crc.h" + #include "utils/timestamp.h" + + + /* + * The overall layout of an XLOG record is: + * Fixed-size header (XLogRecord struct) + * rmgr-specific data + * BkpBlock + * backup block data + * BkpBlock + * backup block data + * ... + * + * where there can be zero to three backup blocks (as signaled by xl_info flag + * bits). XLogRecord structs always start on MAXALIGN boundaries in the WAL + * files, and we round up SizeOfXLogRecord so that the rmgr data is also + * guaranteed to begin on a MAXALIGN boundary. However, no padding is added + * to align BkpBlock structs or backup block data. + * + * NOTE: xl_len counts only the rmgr data, not the XLogRecord header, + * and also not any backup blocks. xl_tot_len counts everything. Neither + * length field is rounded up to an alignment boundary. + */ + typedef struct XLogRecord + { + pg_crc32 xl_crc; /* CRC for this record */ + XLogRecPtr xl_prev; /* ptr to previous record in log */ + TransactionId xl_xid; /* xact id */ + uint32 xl_tot_len; /* total len of entire record */ + uint32 xl_len; /* total len of rmgr data */ + uint8 xl_info; /* flag bits, see below */ + RmgrId xl_rmid; /* resource manager for this record */ + + /* Depending on MAXALIGN, there are either 2 or 6 wasted bytes here */ + + /* ACTUAL LOG DATA FOLLOWS AT END OF STRUCT */ + + } XLogRecord; + + #define SizeOfXLogRecord MAXALIGN(sizeof(XLogRecord)) + + #define XLogRecGetData(record) ((char*) (record) + SizeOfXLogRecord) + + /* + * XLOG uses only low 4 bits of xl_info. High 4 bits may be used by rmgr. + */ + #define XLR_INFO_MASK 0x0F + + /* + * If we backed up any disk blocks with the XLOG record, we use flag bits in + * xl_info to signal it. We support backup of up to 3 disk blocks per XLOG + * record. + */ + #define XLR_BKP_BLOCK_MASK 0x0E /* all info bits used for bkp blocks */ + #define XLR_MAX_BKP_BLOCKS 3 + #define XLR_SET_BKP_BLOCK(iblk) (0x08 >> (iblk)) + #define XLR_BKP_BLOCK_1 XLR_SET_BKP_BLOCK(0) /* 0x08 */ + #define XLR_BKP_BLOCK_2 XLR_SET_BKP_BLOCK(1) /* 0x04 */ + #define XLR_BKP_BLOCK_3 XLR_SET_BKP_BLOCK(2) /* 0x02 */ + + /* + * Bit 0 of xl_info is set if the backed-up blocks could safely be removed + * from a compressed version of XLOG (that is, they are backed up only to + * prevent partial-page-write problems, and not to ensure consistency of PITR + * recovery). The compression algorithm would need to extract data from the + * blocks to create an equivalent non-full-page XLOG record. + */ + #define XLR_BKP_REMOVABLE 0x01 + + /* Sync methods */ + #define SYNC_METHOD_FSYNC 0 + #define SYNC_METHOD_FDATASYNC 1 + #define SYNC_METHOD_OPEN 2 /* for O_SYNC */ + #define SYNC_METHOD_FSYNC_WRITETHROUGH 3 + #define SYNC_METHOD_OPEN_DSYNC 4 /* for O_DSYNC */ + extern int sync_method; + + /* + * The rmgr data to be written by XLogInsert() is defined by a chain of + * one or more XLogRecData structs. (Multiple structs would be used when + * parts of the source data aren't physically adjacent in memory, or when + * multiple associated buffers need to be specified.) + * + * If buffer is valid then XLOG will check if buffer must be backed up + * (ie, whether this is first change of that page since last checkpoint). + * If so, the whole page contents are attached to the XLOG record, and XLOG + * sets XLR_BKP_BLOCK_X bit in xl_info. Note that the buffer must be pinned + * and exclusive-locked by the caller, so that it won't change under us. + * NB: when the buffer is backed up, we DO NOT insert the data pointed to by + * this XLogRecData struct into the XLOG record, since we assume it's present + * in the buffer. Therefore, rmgr redo routines MUST pay attention to + * XLR_BKP_BLOCK_X to know what is actually stored in the XLOG record. + * The i'th XLR_BKP_BLOCK bit corresponds to the i'th distinct buffer + * value (ignoring InvalidBuffer) appearing in the rdata chain. + * + * When buffer is valid, caller must set buffer_std to indicate whether the + * page uses standard pd_lower/pd_upper header fields. If this is true, then + * XLOG is allowed to omit the free space between pd_lower and pd_upper from + * the backed-up page image. Note that even when buffer_std is false, the + * page MUST have an LSN field as its first eight bytes! + * + * Note: data can be NULL to indicate no rmgr data associated with this chain + * entry. This can be sensible (ie, not a wasted entry) if buffer is valid. + * The implication is that the buffer has been changed by the operation being + * logged, and so may need to be backed up, but the change can be redone using + * only information already present elsewhere in the XLOG entry. + */ + typedef struct XLogRecData + { + char *data; /* start of rmgr data to include */ + uint32 len; /* length of rmgr data to include */ + Buffer buffer; /* buffer associated with data, if any */ + bool buffer_std; /* buffer has standard pd_lower/pd_upper */ + struct XLogRecData *next; /* next struct in chain, or NULL */ + } XLogRecData; + + extern TimeLineID ThisTimeLineID; /* current TLI */ + extern bool InRecovery; + extern XLogRecPtr XactLastRecEnd; + + /* these variables are GUC parameters related to XLOG */ + extern int CheckPointSegments; + extern int XLOGbuffers; + extern bool XLogArchiveMode; + extern char *XLogArchiveCommand; + extern int XLogArchiveTimeout; + extern bool log_checkpoints; + + #define XLogArchivingActive() (XLogArchiveMode) + #define XLogArchiveCommandSet() (XLogArchiveCommand[0] != '\0') + + #ifdef WAL_DEBUG + extern bool XLOG_DEBUG; + #endif + + /* + * OR-able request flag bits for checkpoints. The "cause" bits are used only + * for logging purposes. Note: the flags must be defined so that it's + * sensible to OR together request flags arising from different requestors. + */ + + /* These directly affect the behavior of CreateCheckPoint and subsidiaries */ + #define CHECKPOINT_IS_SHUTDOWN 0x0001 /* Checkpoint is for shutdown */ + #define CHECKPOINT_IMMEDIATE 0x0002 /* Do it without delays */ + #define CHECKPOINT_FORCE 0x0004 /* Force even if no activity */ + /* These are important to RequestCheckpoint */ + #define CHECKPOINT_WAIT 0x0008 /* Wait for completion */ + /* These indicate the cause of a checkpoint request */ + #define CHECKPOINT_CAUSE_XLOG 0x0010 /* XLOG consumption */ + #define CHECKPOINT_CAUSE_TIME 0x0020 /* Elapsed time */ + + /* Checkpoint statistics */ + typedef struct CheckpointStatsData + { + TimestampTz ckpt_start_t; /* start of checkpoint */ + TimestampTz ckpt_write_t; /* start of flushing buffers */ + TimestampTz ckpt_sync_t; /* start of fsyncs */ + TimestampTz ckpt_sync_end_t; /* end of fsyncs */ + TimestampTz ckpt_end_t; /* end of checkpoint */ + + int ckpt_bufs_written; /* # of buffers written */ + + int ckpt_segs_added; /* # of new xlog segments created */ + int ckpt_segs_removed; /* # of xlog segments deleted */ + int ckpt_segs_recycled; /* # of xlog segments recycled */ + } CheckpointStatsData; + + extern CheckpointStatsData CheckpointStats; + + + extern XLogRecPtr XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata); + extern void XLogFlush(XLogRecPtr RecPtr); + extern void XLogBackgroundFlush(void); + extern void XLogAsyncCommitFlush(void); + extern bool XLogNeedsFlush(XLogRecPtr RecPtr); + + extern void XLogSetAsyncCommitLSN(XLogRecPtr record); + + extern void RestoreBkpBlocks(XLogRecPtr lsn, XLogRecord *record, bool cleanup); + + extern void xlog_redo(XLogRecPtr lsn, XLogRecord *record); + extern void xlog_desc(StringInfo buf, uint8 xl_info, char *rec); + + extern void UpdateControlFile(void); + extern Size XLOGShmemSize(void); + extern void XLOGShmemInit(void); + extern void BootStrapXLOG(void); + extern void StartupXLOG(void); + extern void ShutdownXLOG(int code, Datum arg); + extern void InitXLOGAccess(void); + extern void CreateCheckPoint(int flags); + extern void XLogPutNextOid(Oid nextOid); + extern XLogRecPtr GetRedoRecPtr(void); + extern XLogRecPtr GetInsertRecPtr(void); + extern void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch); + + #endif /* XLOG_H */ diff -rcN Postgresql-CVS-20090313.org/src/include/access/xlog_internal.h Postgresql-CVS-20090313/src/include/access/xlog_internal.h *** Postgresql-CVS-20090313.org/src/include/access/xlog_internal.h 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/include/access/xlog_internal.h 2009-03-13 16:37:09.000000000 +0900 *************** *** 235,240 **** --- 235,241 ---- void (*rm_startup) (void); void (*rm_cleanup) (void); bool (*rm_safe_restartpoint) (void); + bool (*rm_readahead) (XLogRecPtr lsn, XLogRecord *rptr); } RmgrData; extern const RmgrData RmgrTable[]; diff -rcN Postgresql-CVS-20090313.org/src/include/commands/sequence.h Postgresql-CVS-20090313/src/include/commands/sequence.h *** Postgresql-CVS-20090313.org/src/include/commands/sequence.h 2009-03-13 14:23:03.000000000 +0900 --- Postgresql-CVS-20090313/src/include/commands/sequence.h 2009-03-13 16:37:09.000000000 +0900 *************** *** 98,102 **** --- 98,103 ---- extern void seq_redo(XLogRecPtr lsn, XLogRecord *rptr); extern void seq_desc(StringInfo buf, uint8 xl_info, char *rec); + extern bool seq_readahead(XLogRecPtr lsn, XLogRecord *record); #endif /* SEQUENCE_H */