Re: pgstattuple extension for indexes

Applied.

---------------------------------------------------------------------------

Satoshi Nagayasu wrote:
> Thanks Bruce,
>
> Here are updated Japanese README, and uninstall_pgstattuple.sql.
>
> Bruce Momjian wrote:
> > Patch applied. Thanks.
> >
> > I updated the README documentation for the new functions, attached. I
> > could not update the Japanese version of the README.
> >
> > ---------------------------------------------------------------------------
> >
> >
> > Satoshi Nagayasu wrote:
> >> Bruce,
> >>
> >> Attached patch has been cleaned up,
> >> and modified to be able to work with CVS HEAD.
> >>
> >> Thanks.
> >>
> >> Satoshi Nagayasu wrote:
> >>> Alvaro,
> >>>
> >>> Alvaro Herrera wrote:
> >>>> Huh, I bet it works with 8.1.4, but it doesn't work on CVS HEAD:
> >>>>
> >>>> /pgsql/source/00orig/contrib/pgstattuple/pgstatindex.c: In function 'GetBTPageStatistics':
> >>>> /pgsql/source/00orig/contrib/pgstattuple/pgstatindex.c:182: error: 'BTItem' undeclared (first use in this function)
> >>>>
> >>>>
> >>>> While you're at it, please consider removing C++ style comments and
> >>>> unused code.
> >>>>
> >>>> Formatting is way off as well, but I guess that is easily fixed with
> >>>> pgindent.
> >>> Thanks for comments. I'm going to fix my patch from now.
> >>>
> >>>> Regarding the pg_relpages function, why do you think it's necessary?
> >>>> (It returns the true number of blocks of a given relation). It may
> >>>> belong into core given a reasonable use case, but otherwise it doesn't
> >>>> seem to belong into pgstatindex (or pgstattuple for that matter).
> >>> I wanted to sample some pages from the table/index, and get their statistics
> >>> to know table/index conditions. I know pgstattuple() reports table
> >>> statistics, however, pgstattuple() generates heavy CPU and I/O load.
> >>>
> >>> When we need to sample some pages from table/index, we need to know
> >>> true number of blocks.
> >>>
> >>> I have another function, called pgstatpage(), to get information inside
> >>> a single block/page statistics of the table. pg_relpages() will be used
> >>> with this.
> >>>
> >>> Sorry for not mentioned in previous post about pgstatpage(),
> >>> but I've remembered about it just now.
> >>>
> >>> Many memories in my brain have already `paged-out` (too busy in last few months),
> >>> and some of them got `out-of-memory`. :^)
> >>>
> >>> Thanks.
> >>
> >> --
> >> NAGAYASU Satoshi <nagayasus(at)nttdata(dot)co(dot)jp>
> >> Phone: +81-3-3523-8122
> >
> >> diff -ruN pgstattuple.orig/Makefile pgstattuple/Makefile
> >> --- pgstattuple.orig/Makefile 2006-02-27 21:54:40.000000000 +0900
> >> +++ pgstattuple/Makefile 2006-08-14 09:28:58.000000000 +0900
> >> @@ -6,7 +6,7 @@
> >> #
> >> #-------------------------------------------------------------------------
> >>
> >> -SRCS = pgstattuple.c
> >> +SRCS = pgstattuple.c pgstatindex.c
> >>
> >> MODULE_big = pgstattuple
> >> OBJS = $(SRCS:.c=.o)
> >> diff -ruN pgstattuple.orig/pgstatindex.c pgstattuple/pgstatindex.c
> >> --- pgstattuple.orig/pgstatindex.c 1970-01-01 09:00:00.000000000 +0900
> >> +++ pgstattuple/pgstatindex.c 2006-08-14 11:24:23.000000000 +0900
> >> @@ -0,0 +1,706 @@
> >> +/*
> >> + * pgstatindex
> >> + *
> >> + * Copyright (c) 2006 Satoshi Nagayasu <nagayasus(at)nttdata(dot)co(dot)jp>
> >> + *
> >> + * Permission to use, copy, modify, and distribute this software and
> >> + * its documentation for any purpose, without fee, and without a
> >> + * written agreement is hereby granted, provided that the above
> >> + * copyright notice and this paragraph and the following two
> >> + * paragraphs appear in all copies.
> >> + *
> >> + * IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
> >> + * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
> >> + * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
> >> + * DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
> >> + * OF THE POSSIBILITY OF SUCH DAMAGE.
> >> + *
> >> + * THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
> >> + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
> >> + * A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
> >> + * IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
> >> + * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
> >> + */
> >> +
> >> +#include "postgres.h"
> >> +
> >> +#include "fmgr.h"
> >> +#include "funcapi.h"
> >> +#include "access/heapam.h"
> >> +#include "access/itup.h"
> >> +#include "access/nbtree.h"
> >> +#include "access/transam.h"
> >> +#include "catalog/namespace.h"
> >> +#include "catalog/pg_type.h"
> >> +#include "utils/builtins.h"
> >> +#include "utils/inval.h"
> >> +
> >> +PG_FUNCTION_INFO_V1(pgstatindex);
> >> +PG_FUNCTION_INFO_V1(bt_metap);
> >> +PG_FUNCTION_INFO_V1(bt_page_items);
> >> +PG_FUNCTION_INFO_V1(bt_page_stats);
> >> +PG_FUNCTION_INFO_V1(pg_relpages);
> >> +
> >> +extern Datum pgstatindex(PG_FUNCTION_ARGS);
> >> +extern Datum bt_metap(PG_FUNCTION_ARGS);
> >> +extern Datum bt_page_items(PG_FUNCTION_ARGS);
> >> +extern Datum bt_page_stats(PG_FUNCTION_ARGS);
> >> +extern Datum pg_relpages(PG_FUNCTION_ARGS);
> >> +
> >> +#define PGSTATINDEX_TYPE "public.pgstatindex_type"
> >> +#define PGSTATINDEX_NCOLUMNS 10
> >> +
> >> +#define BTMETAP_TYPE "public.bt_metap_type"
> >> +#define BTMETAP_NCOLUMNS 6
> >> +
> >> +#define BTPAGEITEMS_TYPE "public.bt_page_items_type"
> >> +#define BTPAGEITEMS_NCOLUMNS 6
> >> +
> >> +#define BTPAGESTATS_TYPE "public.bt_page_stats_type"
> >> +#define BTPAGESTATS_NCOLUMNS 11
> >> +
> >> +
> >> +#define IS_INDEX(r) ((r)->rd_rel->relkind == 'i')
> >> +#define IS_BTREE(r) ((r)->rd_rel->relam == BTREE_AM_OID)
> >> +
> >> +#define CHECK_PAGE_OFFSET_RANGE(page, offset) { \
> >> + if ( !(FirstOffsetNumber<=(offset) && \
> >> + (offset)<=PageGetMaxOffsetNumber(page)) ) \
> >> + elog(ERROR, "Page offset number out of range."); }
> >> +
> >> +#define CHECK_RELATION_BLOCK_RANGE(rel, blkno) { \
> >> + if ( (blkno)<0 && RelationGetNumberOfBlocks((rel))<=(blkno) ) \
> >> + elog(ERROR, "Block number out of range."); }
> >> +
> >> +/* ------------------------------------------------
> >> + * structure for single btree page statistics
> >> + * ------------------------------------------------
> >> + */
> >> +typedef struct BTPageStat
> >> +{
> >> + uint32 blkno;
> >> + uint32 live_items;
> >> + uint32 dead_items;
> >> + uint32 page_size;
> >> + uint32 max_avail;
> >> + uint32 free_size;
> >> + uint32 avg_item_size;
> >> + uint32 fragments;
> >> + char type;
> >> +
> >> + /* opaque data */
> >> + BlockNumber btpo_prev;
> >> + BlockNumber btpo_next;
> >> + union
> >> + {
> >> + uint32 level;
> >> + TransactionId xact;
> >> + } btpo;
> >> + uint16 btpo_flags;
> >> + BTCycleId btpo_cycleid;
> >> +} BTPageStat;
> >> +
> >> +/* ------------------------------------------------
> >> + * A structure for a whole btree index statistics
> >> + * used by pgstatindex().
> >> + * ------------------------------------------------
> >> + */
> >> +typedef struct BTIndexStat
> >> +{
> >> + uint32 magic;
> >> + uint32 version;
> >> + BlockNumber root_blkno;
> >> + uint32 level;
> >> +
> >> + BlockNumber fastroot;
> >> + uint32 fastlevel;
> >> +
> >> + uint32 live_items;
> >> + uint32 dead_items;
> >> +
> >> + uint32 root_pages;
> >> + uint32 internal_pages;
> >> + uint32 leaf_pages;
> >> + uint32 empty_pages;
> >> + uint32 deleted_pages;
> >> +
> >> + uint32 page_size;
> >> + uint32 avg_item_size;
> >> +
> >> + uint32 max_avail;
> >> + uint32 free_space;
> >> +
> >> + uint32 fragments;
> >> +} BTIndexStat;
> >> +
> >> +/* -------------------------------------------------
> >> + * GetBTPageStatistics()
> >> + *
> >> + * Collect statistics of single b-tree leaf page
> >> + * -------------------------------------------------
> >> + */
> >> +static bool
> >> +GetBTPageStatistics(BlockNumber blkno, Buffer buffer, BTPageStat * stat)
> >> +{
> >> + Page page = BufferGetPage(buffer);
> >> + PageHeader phdr = (PageHeader) page;
> >> + OffsetNumber maxoff = PageGetMaxOffsetNumber(page);
> >> + BTPageOpaque opaque = (BTPageOpaque) PageGetSpecialPointer(page);
> >> + int item_size = 0;
> >> + int off;
> >> +
> >> + stat->blkno = blkno;
> >> +
> >> + stat->max_avail = BLCKSZ - (BLCKSZ - phdr->pd_special + SizeOfPageHeaderData);
> >> +
> >> + stat->dead_items = stat->live_items = 0;
> >> +
> >> + stat->page_size = PageGetPageSize(page);
> >> +
> >> + /* page type (flags) */
> >> + if (P_ISDELETED(opaque))
> >> + {
> >> + stat->type = 'd';
> >> + return true;
> >> + }
> >> + else if (P_IGNORE(opaque))
> >> + stat->type = 'e';
> >> + else if (P_ISLEAF(opaque))
> >> + stat->type = 'l';
> >> + else if (P_ISROOT(opaque))
> >> + stat->type = 'r';
> >> + else
> >> + stat->type = 'i';
> >> +
> >> + /* btpage opaque data */
> >> + stat->btpo_prev = opaque->btpo_prev;
> >> + stat->btpo_next = opaque->btpo_next;
> >> + if (P_ISDELETED(opaque))
> >> + stat->btpo.xact = opaque->btpo.xact;
> >> + else
> >> + stat->btpo.level = opaque->btpo.level;
> >> + stat->btpo_flags = opaque->btpo_flags;
> >> + stat->btpo_cycleid = opaque->btpo_cycleid;
> >> +
> >> + /*----------------------------------------------
> >> + * If a next leaf is on the previous block,
> >> + * it means a fragmentation.
> >> + *----------------------------------------------
> >> + */
> >> + stat->fragments = 0;
> >> + if (stat->type == 'l')
> >> + {
> >> + if (opaque->btpo_next != P_NONE && opaque->btpo_next < blkno)
> >> + stat->fragments++;
> >> + }
> >> +
> >> + /* count live and dead tuples, and free space */
> >> + for (off = FirstOffsetNumber; off <= maxoff; off++)
> >> + {
> >> + IndexTuple itup;
> >> +
> >> + ItemId id = PageGetItemId(page, off);
> >> +
> >> + itup = (IndexTuple) PageGetItem(page, id);
> >> +
> >> + item_size += IndexTupleSize(itup);
> >> +
> >> + if (!ItemIdDeleted(id))
> >> + stat->live_items++;
> >> + else
> >> + stat->dead_items++;
> >> + }
> >> + stat->free_size = PageGetFreeSpace(page);
> >> +
> >> + if ((stat->live_items + stat->dead_items) > 0)
> >> + stat->avg_item_size = item_size / (stat->live_items + stat->dead_items);
> >> + else
> >> + stat->avg_item_size = 0;
> >> +
> >> + return true;
> >> +}
> >> +
> >> +
> >> +/* ------------------------------------------------------
> >> + * pgstatindex()
> >> + *
> >> + * Usage: SELECT * FROM pgstatindex('t1_pkey');
> >> + * ------------------------------------------------------
> >> + */
> >> +Datum
> >> +pgstatindex(PG_FUNCTION_ARGS)
> >> +{
> >> + text *relname = PG_GETARG_TEXT_P(0);
> >> + Relation rel;
> >> + RangeVar *relrv;
> >> + Datum result;
> >> + uint32 nblocks;
> >> + uint32 blkno;
> >> + BTIndexStat indexStat;
> >> +
> >> + relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
> >> + rel = relation_openrv(relrv, AccessShareLock);
> >> +
> >> + if (!IS_INDEX(rel) || !IS_BTREE(rel))
> >> + elog(ERROR, "pgstatindex() can be used only on b-tree index.");
> >> +
> >> + /*-------------------
> >> + * Read a metapage
> >> + *-------------------
> >> + */
> >> + {
> >> + Buffer buffer = ReadBuffer(rel, 0);
> >> + Page page = BufferGetPage(buffer);
> >> + BTMetaPageData *metad = BTPageGetMeta(page);
> >> +
> >> + indexStat.magic = metad->btm_magic;
> >> + indexStat.version = metad->btm_version;
> >> + indexStat.root_blkno = metad->btm_root;
> >> + indexStat.level = metad->btm_level;
> >> + indexStat.fastroot = metad->btm_fastroot;
> >> + indexStat.fastlevel = metad->btm_fastlevel;
> >> +
> >> + ReleaseBuffer(buffer);
> >> + }
> >> +
> >> + nblocks = RelationGetNumberOfBlocks(rel);
> >> +
> >> + /* -- init stat -- */
> >> + indexStat.fragments = 0;
> >> +
> >> + indexStat.root_pages = 0;
> >> + indexStat.leaf_pages = 0;
> >> + indexStat.internal_pages = 0;
> >> + indexStat.empty_pages = 0;
> >> + indexStat.deleted_pages = 0;
> >> +
> >> + indexStat.max_avail = 0;
> >> + indexStat.free_space = 0;
> >> +
> >> + /*-----------------------
> >> + * Scan all blocks
> >> + *-----------------------
> >> + */
> >> + for (blkno = 1; blkno < nblocks; blkno++)
> >> + {
> >> + Buffer buffer = ReadBuffer(rel, blkno);
> >> + BTPageStat stat;
> >> +
> >> + /* scan one page */
> >> + stat.blkno = blkno;
> >> + GetBTPageStatistics(blkno, buffer, &stat);
> >> +
> >> + /*---------------------
> >> + * page status (type)
> >> + *---------------------
> >> + */
> >> + switch (stat.type)
> >> + {
> >> + case 'd':
> >> + indexStat.deleted_pages++;
> >> + break;
> >> + case 'l':
> >> + indexStat.leaf_pages++;
> >> + break;
> >> + case 'i':
> >> + indexStat.internal_pages++;
> >> + break;
> >> + case 'e':
> >> + indexStat.empty_pages++;
> >> + break;
> >> + case 'r':
> >> + indexStat.root_pages++;
> >> + break;
> >> + default:
> >> + elog(ERROR, "unknown page status.");
> >> + }
> >> +
> >> + /* -- leaf fragmentation -- */
> >> + indexStat.fragments += stat.fragments;
> >> +
> >> + if (stat.type == 'l')
> >> + {
> >> + indexStat.max_avail += stat.max_avail;
> >> + indexStat.free_space += stat.free_size;
> >> + }
> >> +
> >> + ReleaseBuffer(buffer);
> >> + }
> >> +
> >> + relation_close(rel, AccessShareLock);
> >> +
> >> + /*----------------------------
> >> + * Build a result tuple
> >> + *----------------------------
> >> + */
> >> + {
> >> + TupleDesc tupleDesc;
> >> + int j;
> >> + char *values[PGSTATINDEX_NCOLUMNS];
> >> +
> >> + HeapTupleData tupleData;
> >> + HeapTuple tuple = &tupleData;
> >> +
> >> + tupleDesc = RelationNameGetTupleDesc(PGSTATINDEX_TYPE);
> >> +
> >> + j = 0;
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", indexStat.version);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", indexStat.level);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", (indexStat.root_pages +
> >> + indexStat.leaf_pages +
> >> + indexStat.internal_pages +
> >> + indexStat.deleted_pages +
> >> + indexStat.empty_pages) * BLCKSZ);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", indexStat.root_blkno);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", indexStat.internal_pages);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", indexStat.leaf_pages);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", indexStat.empty_pages);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", indexStat.deleted_pages);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%.2f", 100.0 - (float) indexStat.free_space / (float) indexStat.max_avail * 100.0);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%.2f", (float) indexStat.fragments / (float) indexStat.leaf_pages * 100.0);
> >> +
> >> + tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
> >> + values);
> >> +
> >> + result = TupleGetDatum(TupleDescGetSlot(tupleDesc), tuple);
> >> + }
> >> +
> >> + PG_RETURN_DATUM(result);
> >> +}
> >> +
> >> +/* -----------------------------------------------
> >> + * bt_page()
> >> + *
> >> + * Usage: SELECT * FROM bt_page('t1_pkey', 0);
> >> + * -----------------------------------------------
> >> + */
> >> +Datum
> >> +bt_page_stats(PG_FUNCTION_ARGS)
> >> +{
> >> + text *relname = PG_GETARG_TEXT_P(0);
> >> + uint32 blkno = PG_GETARG_UINT32(1);
> >> + Buffer buffer;
> >> +
> >> + Relation rel;
> >> + RangeVar *relrv;
> >> + Datum result;
> >> +
> >> + relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
> >> + rel = relation_openrv(relrv, AccessShareLock);
> >> +
> >> + CHECK_RELATION_BLOCK_RANGE(rel, blkno);
> >> +
> >> + buffer = ReadBuffer(rel, blkno);
> >> +
> >> + if (!IS_INDEX(rel) || !IS_BTREE(rel))
> >> + elog(ERROR, "bt_page_stats() can be used only on b-tree index.");
> >> +
> >> + if (blkno == 0)
> >> + elog(ERROR, "Block 0 is a meta page.");
> >> +
> >> + {
> >> + HeapTuple tuple;
> >> + TupleDesc tupleDesc;
> >> + int j;
> >> + char *values[BTPAGESTATS_NCOLUMNS];
> >> +
> >> + BTPageStat stat;
> >> +
> >> + GetBTPageStatistics(blkno, buffer, &stat);
> >> +
> >> + tupleDesc = RelationNameGetTupleDesc(BTPAGESTATS_TYPE);
> >> +
> >> + j = 0;
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", stat.blkno);
> >> +
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%c", stat.type);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", stat.live_items);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", stat.dead_items);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", stat.avg_item_size);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", stat.page_size);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", stat.free_size);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", stat.btpo_prev);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", stat.btpo_next);
> >> +
> >> + values[j] = palloc(32);
> >> + if (stat.type == 'd')
> >> + snprintf(values[j++], 32, "%d", stat.btpo.xact);
> >> + else
> >> + snprintf(values[j++], 32, "%d", stat.btpo.level);
> >> +
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", stat.btpo_flags);
> >> +
> >> + tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
> >> + values);
> >> +
> >> + result = TupleGetDatum(TupleDescGetSlot(tupleDesc), tuple);
> >> + }
> >> +
> >> + ReleaseBuffer(buffer);
> >> +
> >> + relation_close(rel, AccessShareLock);
> >> +
> >> + PG_RETURN_DATUM(result);
> >> +}
> >> +
> >> +/*-------------------------------------------------------
> >> + * bt_page_items()
> >> + *
> >> + * Get IndexTupleData set in a leaf page
> >> + *
> >> + * Usage: SELECT * FROM bt_page_items('t1_pkey', 0);
> >> + *-------------------------------------------------------
> >> + */
> >> +/* ---------------------------------------------------
> >> + * data structure for SRF to hold a scan information
> >> + * ---------------------------------------------------
> >> + */
> >> +struct user_args
> >> +{
> >> + TupleDesc tupd;
> >> + Relation rel;
> >> + Buffer buffer;
> >> + Page page;
> >> + uint16 offset;
> >> +};
> >> +
> >> +Datum
> >> +bt_page_items(PG_FUNCTION_ARGS)
> >> +{
> >> + text *relname = PG_GETARG_TEXT_P(0);
> >> + uint32 blkno = PG_GETARG_UINT32(1);
> >> +
> >> + RangeVar *relrv;
> >> + Datum result;
> >> + char *values[BTPAGEITEMS_NCOLUMNS];
> >> + BTPageOpaque opaque;
> >> + HeapTuple tuple;
> >> + ItemId id;
> >> +
> >> + FuncCallContext *fctx;
> >> + MemoryContext mctx;
> >> + struct user_args *uargs = NULL;
> >> +
> >> + if (blkno == 0)
> >> + elog(ERROR, "Block 0 is a meta page.");
> >> +
> >> + if (SRF_IS_FIRSTCALL())
> >> + {
> >> + fctx = SRF_FIRSTCALL_INIT();
> >> + mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
> >> +
> >> + uargs = palloc(sizeof(struct user_args));
> >> +
> >> + uargs->tupd = RelationNameGetTupleDesc(BTPAGEITEMS_TYPE);
> >> + uargs->offset = FirstOffsetNumber;
> >> +
> >> + relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
> >> + uargs->rel = relation_openrv(relrv, AccessShareLock);
> >> +
> >> + CHECK_RELATION_BLOCK_RANGE(uargs->rel, blkno);
> >> +
> >> + uargs->buffer = ReadBuffer(uargs->rel, blkno);
> >> +
> >> + if (!IS_INDEX(uargs->rel) || !IS_BTREE(uargs->rel))
> >> + elog(ERROR, "bt_page_items() can be used only on b-tree index.");
> >> +
> >> + uargs->page = BufferGetPage(uargs->buffer);
> >> +
> >> + opaque = (BTPageOpaque) PageGetSpecialPointer(uargs->page);
> >> +
> >> + if (P_ISDELETED(opaque))
> >> + elog(NOTICE, "bt_page_items(): this page is deleted.");
> >> +
> >> + fctx->max_calls = PageGetMaxOffsetNumber(uargs->page);
> >> + fctx->user_fctx = uargs;
> >> +
> >> + MemoryContextSwitchTo(mctx);
> >> + }
> >> +
> >> + fctx = SRF_PERCALL_SETUP();
> >> + uargs = fctx->user_fctx;
> >> +
> >> + if (fctx->call_cntr < fctx->max_calls)
> >> + {
> >> + IndexTuple itup;
> >> +
> >> + id = PageGetItemId(uargs->page, uargs->offset);
> >> +
> >> + if (!ItemIdIsValid(id))
> >> + elog(ERROR, "Invalid ItemId.");
> >> +
> >> + itup = (IndexTuple) PageGetItem(uargs->page, id);
> >> +
> >> + {
> >> + int j = 0;
> >> +
> >> + BlockNumber blkno = BlockIdGetBlockNumber(&(itup->t_tid.ip_blkid));
> >> +
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", uargs->offset);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "(%u,%u)", blkno, itup->t_tid.ip_posid);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", IndexTupleSize(itup));
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%c", IndexTupleHasNulls(itup) ? 't' : 'f');
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%c", IndexTupleHasVarwidths(itup) ? 't' : 'f');
> >> +
> >> + {
> >> + int off;
> >> + char *dump;
> >> + char *ptr = (char *) itup + IndexInfoFindDataOffset(itup->t_info);
> >> +
> >> + dump = palloc(IndexTupleSize(itup) * 3);
> >> + memset(dump, 0, IndexTupleSize(itup) * 3);
> >> +
> >> + for (off = 0;
> >> + off < IndexTupleSize(itup) - IndexInfoFindDataOffset(itup->t_info);
> >> + off++)
> >> + {
> >> + if (dump[0] == '\0')
> >> + sprintf(dump, "%02x", *(ptr + off) & 0xff);
> >> + else
> >> + {
> >> + char buf[4];
> >> +
> >> + sprintf(buf, " %02x", *(ptr + off) & 0xff);
> >> + strcat(dump, buf);
> >> + }
> >> + }
> >> + values[j] = dump;
> >> + }
> >> +
> >> + tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(uargs->tupd), values);
> >> + result = TupleGetDatum(TupleDescGetSlot(uargs->tupd), tuple);
> >> + }
> >> +
> >> + uargs->offset = uargs->offset + 1;
> >> +
> >> + SRF_RETURN_NEXT(fctx, result);
> >> + }
> >> + else
> >> + {
> >> + ReleaseBuffer(uargs->buffer);
> >> + relation_close(uargs->rel, AccessShareLock);
> >> +
> >> + SRF_RETURN_DONE(fctx);
> >> + }
> >> +}
> >> +
> >> +
> >> +/* ------------------------------------------------
> >> + * bt_metap()
> >> + *
> >> + * Get a btree meta-page information
> >> + *
> >> + * Usage: SELECT * FROM bt_metap('t1_pkey')
> >> + * ------------------------------------------------
> >> + */
> >> +Datum
> >> +bt_metap(PG_FUNCTION_ARGS)
> >> +{
> >> + text *relname = PG_GETARG_TEXT_P(0);
> >> + Buffer buffer;
> >> +
> >> + Relation rel;
> >> + RangeVar *relrv;
> >> + Datum result;
> >> +
> >> + relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
> >> + rel = relation_openrv(relrv, AccessShareLock);
> >> +
> >> + if (!IS_INDEX(rel) || !IS_BTREE(rel))
> >> + elog(ERROR, "bt_metap() can be used only on b-tree index.");
> >> +
> >> + buffer = ReadBuffer(rel, 0);
> >> +
> >> + {
> >> + BTMetaPageData *metad;
> >> +
> >> + TupleDesc tupleDesc;
> >> + int j;
> >> + char *values[BTMETAP_NCOLUMNS];
> >> + HeapTuple tuple;
> >> +
> >> + Page page = BufferGetPage(buffer);
> >> +
> >> + metad = BTPageGetMeta(page);
> >> +
> >> + tupleDesc = RelationNameGetTupleDesc(BTMETAP_TYPE);
> >> +
> >> + j = 0;
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", metad->btm_magic);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", metad->btm_version);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", metad->btm_root);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", metad->btm_level);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", metad->btm_fastroot);
> >> + values[j] = palloc(32);
> >> + snprintf(values[j++], 32, "%d", metad->btm_fastlevel);
> >> +
> >> + tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
> >> + values);
> >> +
> >> + result = TupleGetDatum(TupleDescGetSlot(tupleDesc), tuple);
> >> + }
> >> +
> >> + ReleaseBuffer(buffer);
> >> +
> >> + relation_close(rel, AccessShareLock);
> >> +
> >> + PG_RETURN_DATUM(result);
> >> +}
> >> +
> >> +/* --------------------------------------------------------
> >> + * pg_relpages()
> >> + *
> >> + * Get a number of pages of the table/index.
> >> + *
> >> + * Usage: SELECT pg_relpages('t1');
> >> + * SELECT pg_relpages('t1_pkey');
> >> + * --------------------------------------------------------
> >> + */
> >> +Datum
> >> +pg_relpages(PG_FUNCTION_ARGS)
> >> +{
> >> + text *relname = PG_GETARG_TEXT_P(0);
> >> +
> >> + Relation rel;
> >> + RangeVar *relrv;
> >> + int4 relpages;
> >> +
> >> + relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
> >> + rel = relation_openrv(relrv, AccessShareLock);
> >> +
> >> + relpages = RelationGetNumberOfBlocks(rel);
> >> +
> >> + relation_close(rel, AccessShareLock);
> >> +
> >> + PG_RETURN_INT32(relpages);
> >> +}
> >> diff -ruN pgstattuple.orig/pgstattuple.sql.in pgstattuple/pgstattuple.sql.in
> >> --- pgstattuple.orig/pgstattuple.sql.in 2006-02-28 01:09:50.000000000 +0900
> >> +++ pgstattuple/pgstattuple.sql.in 2006-08-14 10:37:32.000000000 +0900
> >> @@ -22,3 +22,96 @@
> >> RETURNS pgstattuple_type
> >> AS 'MODULE_PATHNAME', 'pgstattuplebyid'
> >> LANGUAGE C STRICT;
> >> +
> >> +--
> >> +-- pgstatindex
> >> +--
> >> +DROP TYPE pgstatindex_type CASCADE;
> >> +CREATE TYPE pgstatindex_type AS (
> >> + version int4,
> >> + tree_level int4,
> >> + index_size int4,
> >> + root_block_no int4,
> >> + internal_pages int4,
> >> + leaf_pages int4,
> >> + empty_pages int4,
> >> + deleted_pages int4,
> >> + avg_leaf_density float8,
> >> + leaf_fragmentation float8
> >> +);
> >> +
> >> +CREATE OR REPLACE FUNCTION pgstatindex(text)
> >> +RETURNS pgstatindex_type
> >> +AS 'MODULE_PATHNAME', 'pgstatindex'
> >> +LANGUAGE 'C' STRICT;
> >> +
> >> +--
> >> +-- bt_metap()
> >> +--
> >> +DROP TYPE bt_metap_type CASCADE;
> >> +CREATE TYPE bt_metap_type AS (
> >> + magic int4,
> >> + version int4,
> >> + root int4,
> >> + level int4,
> >> + fastroot int4,
> >> + fastlevel int4
> >> +);
> >> +
> >> +CREATE OR REPLACE FUNCTION bt_metap(text)
> >> +RETURNS bt_metap_type
> >> +AS 'MODULE_PATHNAME', 'bt_metap'
> >> +LANGUAGE 'C' STRICT;
> >> +
> >> +--
> >> +-- bt_page_items()
> >> +--
> >> +DROP TYPE bt_page_items_type CASCADE;
> >> +CREATE TYPE bt_page_items_type AS (
> >> + itemoffset int4,
> >> + ctid tid,
> >> + itemlen int4,
> >> + nulls bool,
> >> + vars bool,
> >> + data text
> >> +);
> >> +
> >> +DROP FUNCTION bt_page_items(text, int4);
> >> +
> >> +CREATE OR REPLACE FUNCTION bt_page_items(text, int4)
> >> +RETURNS SETOF bt_page_items_type
> >> +AS 'MODULE_PATHNAME', 'bt_page_items'
> >> +LANGUAGE 'C' STRICT;
> >> +
> >> +--
> >> +-- bt_page_stats()
> >> +--
> >> +DROP TYPE bt_page_stats_type CASCADE;
> >> +CREATE TYPE bt_page_stats_type AS (
> >> + blkno int4,
> >> + type char,
> >> + live_items int4,
> >> + dead_items int4,
> >> + avg_item_size float,
> >> + page_size int4,
> >> + free_size int4,
> >> + btpo_prev int4,
> >> + btpo_next int4,
> >> + btpo int4,
> >> + btpo_flags int4
> >> +);
> >> +
> >> +DROP FUNCTION bt_page_stats(text, int4);
> >> +
> >> +CREATE OR REPLACE FUNCTION bt_page_stats(text, int4)
> >> +RETURNS bt_page_stats_type
> >> +AS 'MODULE_PATHNAME', 'bt_page_stats'
> >> +LANGUAGE 'C' STRICT;
> >> +
> >> +--
> >> +-- pg_relpages()
> >> +--
> >> +CREATE OR REPLACE FUNCTION pg_relpages(text)
> >> +RETURNS int
> >> +AS 'MODULE_PATHNAME', 'pg_relpages'
> >> +LANGUAGE 'C' STRICT;
> >> diff -ruN pgstattuple.orig/test.sh pgstattuple/test.sh
> >> --- pgstattuple.orig/test.sh 1970-01-01 09:00:00.000000000 +0900
> >> +++ pgstattuple/test.sh 2006-08-14 10:23:08.000000000 +0900
> >> @@ -0,0 +1,27 @@
> >> +#!/bin/sh
> >> +
> >> +PGHOME=/home/snaga/pgsql20060814
> >> +export PATH=${PGHOME}/bin:$PATH
> >> +
> >> +psql -p 9999 pgbench<<EOF
> >> +DROP FUNCTION pgstatindex(text);
> >> +EOF
> >> +
> >> +psql -p 9999 -f ${PGHOME}/share/contrib/pgstattuple.sql pgbench
> >> +
> >> +psql -p 9999 pgbench<<EOF
> >> +SELECT * FROM pg_relpages('accounts_pkey');
> >> +\x
> >> +SELECT * FROM pgstatindex('accounts_pkey');
> >> +SELECT * FROM bt_metap('accounts_pkey');
> >> +\x
> >> +SELECT * FROM bt_page_items('accounts_pkey', 0);
> >> +SELECT * FROM bt_page_items('accounts_pkey', 1) limit 20;
> >> +
> >> +SELECT * FROM bt_page_stats('accounts_pkey', 1);
> >> +\x
> >> +SELECT * FROM bt_page_stats('accounts_pkey', 1);
> >> +SELECT * FROM bt_page_stats('accounts_pkey', 361);
> >> +\x
> >> +SELECT * FROM bt_page_items('accounts_pkey', 361);
> >> +EOF
> >>
> >>
> >> ------------------------------------------------------------------------
> >>
> >> pgstattuple README 2002/08/29 Tatsuo Ishii
> >>
> >> 1. Functions supported:
> >>
> >> pgstattuple
> >> -----------
> >> pgstattuple() returns the relation length, percentage of the "dead"
> >> tuples of a relation and other info. This may help users to determine
> >> whether vacuum is necessary or not. Here is an example session:
> >>
> >> test=> \x
> >> Expanded display is on.
> >> test=> SELECT * FROM pgstattuple('pg_catalog.pg_proc');
> >> -[ RECORD 1 ]------+-------
> >> table_len | 458752
> >> tuple_count | 1470
> >> tuple_len | 438896
> >> tuple_percent | 95.67
> >> dead_tuple_count | 11
> >> dead_tuple_len | 3157
> >> dead_tuple_percent | 0.69
> >> free_space | 8932
> >> free_percent | 1.95
> >>
> >> Here are explanations for each column:
> >>
> >> table_len -- physical relation length in bytes
> >> tuple_count -- number of live tuples
> >> tuple_len -- total tuples length in bytes
> >> tuple_percent -- live tuples in %
> >> dead_tuple_len -- total dead tuples length in bytes
> >> dead_tuple_percent -- dead tuples in %
> >> free_space -- free space in bytes
> >> free_percent -- free space in %
> >>
> >> pg_relpages
> >> -----------
> >> pg_relpages() returns the number of pages in the relation.
> >>
> >> pgstatindex
> >> -----------
> >> pgstatindex() returns an array showing the information about an index:
> >>
> >> test=> \x
> >> Expanded display is on.
> >> test=> SELECT * FROM pgstatindex('pg_cast_oid_index');
> >> -[ RECORD 1 ]------+------
> >> version | 2
> >> tree_level | 0
> >> index_size | 8192
> >> root_block_no | 1
> >> internal_pages | 0
> >> leaf_pages | 1
> >> empty_pages | 0
> >> deleted_pages | 0
> >> avg_leaf_density | 50.27
> >> leaf_fragmentation | 0
> >>
> >> bt_metap
> >> --------
> >> bt_metap() returns information about the btree index metapage:
> >>
> >> test=> SELECT * FROM bt_metap('pg_cast_oid_index');
> >> -[ RECORD 1 ]-----
> >> magic | 340322
> >> version | 2
> >> root | 1
> >> level | 0
> >> fastroot | 1
> >> fastlevel | 0
> >>
> >> bt_page_stats
> >> -------------
> >> bt_page_stats() shows information about single btree pages:
> >>
> >> test=> SELECT * FROM bt_page_stats('pg_cast_oid_index', 1);
> >> -[ RECORD 1 ]-+-----
> >> blkno | 1
> >> type | l
> >> live_items | 256
> >> dead_items | 0
> >> avg_item_size | 12
> >> page_size | 8192
> >> free_size | 4056
> >> btpo_prev | 0
> >> btpo_next | 0
> >> btpo | 0
> >> btpo_flags | 3
> >>
> >> bt_page_items
> >> -------------
> >> bt_page_items() returns information about specific items on btree pages:
> >>
> >> test=> SELECT * FROM bt_page_items('pg_cast_oid_index', 1);
> >> itemoffset | ctid | itemlen | nulls | vars | data
> >> ------------+---------+---------+-------+------+-------------
> >> 1 | (0,1) | 12 | f | f | 23 27 00 00
> >> 2 | (0,2) | 12 | f | f | 24 27 00 00
> >> 3 | (0,3) | 12 | f | f | 25 27 00 00
> >> 4 | (0,4) | 12 | f | f | 26 27 00 00
> >> 5 | (0,5) | 12 | f | f | 27 27 00 00
> >> 6 | (0,6) | 12 | f | f | 28 27 00 00
> >> 7 | (0,7) | 12 | f | f | 29 27 00 00
> >> 8 | (0,8) | 12 | f | f | 2a 27 00 00
> >>
> >>
> >> 2. Installing pgstattuple
> >>
> >> $ make
> >> $ make install
> >> $ psql -e -f /usr/local/pgsql/share/contrib/pgstattuple.sql test
> >>
> >>
> >> 3. Using pgstattuple
> >>
> >> pgstattuple may be called as a relation function and is
> >> defined as follows:
> >>
> >> CREATE OR REPLACE FUNCTION pgstattuple(text) RETURNS pgstattuple_type
> >> AS 'MODULE_PATHNAME', 'pgstattuple'
> >> LANGUAGE C STRICT;
> >>
> >> CREATE OR REPLACE FUNCTION pgstattuple(oid) RETURNS pgstattuple_type
> >> AS 'MODULE_PATHNAME', 'pgstattuplebyid'
> >> LANGUAGE C STRICT;
> >>
> >> The argument is the relation name (optionally it may be qualified)
> >> or the OID of the relation. Note that pgstattuple only returns
> >> one row.
> >>
> >>
> >> 4. Notes
> >>
> >> pgstattuple acquires only a read lock on the relation. So concurrent
> >> update may affect the result.
> >>
> >> pgstattuple judges a tuple is "dead" if HeapTupleSatisfiesNow()
> >> returns false.
> >>
> >>
> >> 5. History
> >>
> >> 2006/06/28
> >>
> >> Extended to work against indexes.
>
>
> --
> NAGAYASU Satoshi <nagayasus(at)nttdata(dot)co(dot)jp>
> Phone: +81-3-3523-8122

> $PostgreSQL: pgsql/contrib/pgstattuple/README.pgstattuple.euc_jp,v 1.7 2006/07/06 02:18:07 momjian Exp $
>
> pgstattuple README 2002/08/22
>
> 1.
>
> pgstattuple
> -----------
> pgstattupleUPDATEDELETE
>
> vacuum
>
>
> pgstattuple() ""
> vacuum
>
>
> test=> \x
> Expanded display is on.
> test=> SELECT * FROM pgstattuple('pg_catalog.pg_proc');
> -[ RECORD 1 ]------+-------
> table_len | 458752
> tuple_count | 1470
> tuple_len | 438896
> tuple_percent | 95.67
> dead_tuple_count | 11
> dead_tuple_len | 3157
> dead_tuple_percent | 0.69
> free_space | 8932
> free_percent | 1.95
>
>
>
> table_len -- ()
> tuple_count --
> tuple_len -- ()
> tuple_percent -- table_lentuple_len
> dead_tuple_len --
> dead_tuple_percent -- table_lentuple_len
> free_space -- ()
> free_percent -- table_lenfree_space
>
> pg_relpages
> -----------
> pg_relpages()
>
> pgstatindex
> -----------
> pgstatindex()
>
> test=> \x
> Expanded display is on.
> test=> SELECT * FROM pgstatindex('pg_cast_oid_index');
> -[ RECORD 1 ]------+------
> version | 2
> tree_level | 0
> index_size | 8192
> root_block_no | 1
> internal_pages | 0
> leaf_pages | 1
> empty_pages | 0
> deleted_pages | 0
> avg_leaf_density | 50.27
> leaf_fragmentation | 0
>
> bt_metap
> --------
> bt_metap() btree
>
> test=> SELECT * FROM bt_metap('pg_cast_oid_index');
> -[ RECORD 1 ]-----
> magic | 340322
> version | 2
> root | 1
> level | 0
> fastroot | 1
> fastlevel | 0
>
> bt_page_stats
> -------------
> bt_page_stats() btree
>
> test=> SELECT * FROM bt_page_stats('pg_cast_oid_index', 1);
> -[ RECORD 1 ]-+-----
> blkno | 1
> type | l
> live_items | 256
> dead_items | 0
> avg_item_size | 12
> page_size | 8192
> free_size | 4056
> btpo_prev | 0
> btpo_next | 0
> btpo | 0
> btpo_flags | 3
>
> bt_page_items
> -------------
> bt_page_items() btree
>
> test=> SELECT * FROM bt_page_items('pg_cast_oid_index', 1);
> itemoffset | ctid | itemlen | nulls | vars | data
> ------------+---------+---------+-------+------+-------------
> 1 | (0,1) | 12 | f | f | 23 27 00 00
> 2 | (0,2) | 12 | f | f | 24 27 00 00
> 3 | (0,3) | 12 | f | f | 25 27 00 00
> 4 | (0,4) | 12 | f | f | 26 27 00 00
> 5 | (0,5) | 12 | f | f | 27 27 00 00
> 6 | (0,6) | 12 | f | f | 28 27 00 00
> 7 | (0,7) | 12 | f | f | 29 27 00 00
> 8 | (0,8) | 12 | f | f | 2a 27 00 00
>
>
> 2. pgstattuple
>
> PostgreSQL/usr/local/pgsqltest
> pgstattuple
>
> $ make
> $ make install
>
>
>
> $ psql -e -f /usr/local/pgsql/share/contrib/pgstattuple.sql test
>
>
> 3. pgstattuple
>
> pgstattuple
>
> CREATE OR REPLACE FUNCTION pgstattuple(text) RETURNS pgstattuple_type
> AS 'MODULE_PATHNAME', 'pgstattuple'
> LANGUAGE C STRICT;
>
> :
>
> pgstattuple_type
>
> pgstattupleAccessShareLock
> pgstattuple
>
>
> pgstattuple
> HeapTupleSatisfiesNow()
>
> 4. pgstattuple
>
> pgstattuple.cpgstattuple
> pgstattuple
>
>
> 5.
>
> 2006/06/28
>
>
>
> 2002/09/04
>
> SRFTom Lane
> README
>
> 2002/08/23
>
> SRF(Set Returning Function)7.3
>
> 2001/12/20 Tom Lane
>
> Fix pgstattuple to acquire a read lock on the target table. This
> prevents embarassments such as having the table dropped or truncated
> partway through the scan. Also, fix free space calculation to include
> pages that currently contain no tuples.
>
> 2001/10/01 PostgreSQL 7.2 contrib module
>
> 2001/08/30 pgstattuple 0.1
>
> -- Adjust this setting to control where the objects get created.
> SET search_path = public;
>
> DROP FUNCTION pgstattuple(oid);
>
> DROP FUNCTION pgstattuple(text);
>
> DROP TYPE pgstattuple_type;
>
> DROP FUNCTION pgstatindex(text);
> DROP FUNCTION bt_metap(text);
> DROP FUNCTION bt_page_items(text, int4);
> DROP FUNCTION bt_page_stats(text, int4);
> DROP FUNCTION pg_relpages(text);
>
> DROP TYPE pgstatindex_type;
> DROP TYPE bt_metap_type;
> DROP TYPE bt_page_items_type;
> DROP TYPE bt_page_stats_type;

--
Bruce Momjian bruce(at)momjian(dot)us
EnterpriseDB http://www.enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +