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Add functions to /contrib/pgstattuple that show index statistics and

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index page contents.

Satoshi Nagayasu
This commit is contained in:
Bruce Momjian 2006-09-02 17:05:29 +00:00
parent 04912899e7
commit 74924d29fa
4 changed files with 914 additions and 40 deletions
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4
contrib/pgstattuple/Makefile
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@ -2,11 +2,11 @@
#
# pgstattuple Makefile
#
# $PostgreSQL: pgsql/contrib/pgstattuple/Makefile,v 1.5 2006/02/27 12:54:39 petere Exp $
# $PostgreSQL: pgsql/contrib/pgstattuple/Makefile,v 1.6 2006/09/02 17:05:29 momjian Exp $
#
#-------------------------------------------------------------------------
SRCS = pgstattuple.c
SRCS = pgstattuple.c pgstatindex.c
MODULE_big = pgstattuple
OBJS = $(SRCS:.c=.o)

151
contrib/pgstattuple/README.pgstattuple
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@ -1,36 +1,108 @@
pgstattuple README 2002/08/29 Tatsuo Ishii
1. What is pgstattuple?
1. Functions supported:
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:
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
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:
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
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 %
2. Installing pgstattuple
@ -38,33 +110,36 @@ free_percent -- free space in %
$ 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:
pgstattuple may be called as a relation function and is
defined as follows:
CREATE OR REPLACE FUNCTION pgstattuple(text) RETURNS pgstattuple_type
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
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.
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 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.
pgstattuple judges a tuple is "dead" if HeapTupleSatisfiesNow()
returns false.
5. History
2006/06/28
2006/06/28
Extended to work against indexes.

706
contrib/pgstattuple/pgstatindex.c Normal file
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@ -0,0 +1,706 @@
/*
* pgstatindex
*
* Copyright (c) 2006 Satoshi Nagayasu <nagayasus@nttdata.co.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);
}

93
contrib/pgstattuple/pgstattuple.sql.in
View File

@ -22,3 +22,96 @@ CREATE OR REPLACE FUNCTION pgstattuple(oid)
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_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;
--
-- 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;
--
-- pg_relpages()
--
CREATE OR REPLACE FUNCTION pg_relpages(text)
RETURNS int
AS 'MODULE_PATHNAME', 'pg_relpages'
LANGUAGE 'C' STRICT;