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Re: pgstattuple extension for indexes

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Satoshi Nagayasu <nagayasus(at)nttdata(dot)co(dot)jp>
Cc: Alvaro Herrera <alvherre(at)commandprompt(dot)com>, pgsql-patches(at)postgresql(dot)org, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, ITAGAKI Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>, ishii(at)sraoss(dot)co(dot)jp
Subject: Re: pgstattuple extension for indexes
Date: 2006-09-04 03:49:13
Message-ID: 200609040349.k843nDv09463@momjian.us (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-patches
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. +

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