mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-12-03 08:00:21 +08:00
44fbe20d62
yesterday's proposal to pghackers. Also remove unnecessary parameters to heap_beginscan, heap_rescan. I modified pg_proc.h to reflect the new numbers of parameters for the AM interface routines, but did not force an initdb because nothing actually looks at those fields.
156 lines
4.4 KiB
C
156 lines
4.4 KiB
C
/*
|
|
* $Header: /cvsroot/pgsql/contrib/pgstattuple/pgstattuple.c,v 1.6 2002/05/20 23:51:40 tgl Exp $
|
|
*
|
|
* Copyright (c) 2001 Tatsuo Ishii
|
|
*
|
|
* 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 "access/heapam.h"
|
|
#include "access/transam.h"
|
|
#include "catalog/namespace.h"
|
|
#include "utils/builtins.h"
|
|
|
|
|
|
PG_FUNCTION_INFO_V1(pgstattuple);
|
|
|
|
extern Datum pgstattuple(PG_FUNCTION_ARGS);
|
|
|
|
/* ----------
|
|
* pgstattuple:
|
|
* returns the percentage of dead tuples
|
|
*
|
|
* C FUNCTION definition
|
|
* pgstattuple(NAME) returns FLOAT8
|
|
* ----------
|
|
*/
|
|
Datum
|
|
pgstattuple(PG_FUNCTION_ARGS)
|
|
{
|
|
text *relname = PG_GETARG_TEXT_P(0);
|
|
RangeVar *relrv;
|
|
Relation rel;
|
|
HeapScanDesc scan;
|
|
HeapTuple tuple;
|
|
BlockNumber nblocks;
|
|
BlockNumber block = 0; /* next block to count free space in */
|
|
BlockNumber tupblock;
|
|
Buffer buffer;
|
|
double table_len;
|
|
uint64 tuple_len = 0;
|
|
uint64 dead_tuple_len = 0;
|
|
uint64 tuple_count = 0;
|
|
uint64 dead_tuple_count = 0;
|
|
double tuple_percent;
|
|
double dead_tuple_percent;
|
|
uint64 free_space = 0; /* free/reusable space in bytes */
|
|
double free_percent; /* free/reusable space in % */
|
|
|
|
relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname,
|
|
"pgstattuple"));
|
|
rel = heap_openrv(relrv, AccessShareLock);
|
|
|
|
nblocks = RelationGetNumberOfBlocks(rel);
|
|
scan = heap_beginscan(rel, SnapshotAny, 0, NULL);
|
|
|
|
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
|
|
{
|
|
if (HeapTupleSatisfiesNow(tuple->t_data))
|
|
{
|
|
tuple_len += tuple->t_len;
|
|
tuple_count++;
|
|
}
|
|
else
|
|
{
|
|
dead_tuple_len += tuple->t_len;
|
|
dead_tuple_count++;
|
|
}
|
|
|
|
/*
|
|
* To avoid physically reading the table twice, try to do the
|
|
* free-space scan in parallel with the heap scan. However,
|
|
* heap_getnext may find no tuples on a given page, so we cannot
|
|
* simply examine the pages returned by the heap scan.
|
|
*/
|
|
tupblock = BlockIdGetBlockNumber(&tuple->t_self.ip_blkid);
|
|
|
|
while (block <= tupblock)
|
|
{
|
|
buffer = ReadBuffer(rel, block);
|
|
free_space += PageGetFreeSpace((Page) BufferGetPage(buffer));
|
|
ReleaseBuffer(buffer);
|
|
block++;
|
|
}
|
|
}
|
|
heap_endscan(scan);
|
|
|
|
while (block < nblocks)
|
|
{
|
|
buffer = ReadBuffer(rel, block);
|
|
free_space += PageGetFreeSpace((Page) BufferGetPage(buffer));
|
|
ReleaseBuffer(buffer);
|
|
block++;
|
|
}
|
|
|
|
heap_close(rel, AccessShareLock);
|
|
|
|
table_len = (double) nblocks *BLCKSZ;
|
|
|
|
if (nblocks == 0)
|
|
{
|
|
tuple_percent = 0.0;
|
|
dead_tuple_percent = 0.0;
|
|
free_percent = 0.0;
|
|
}
|
|
else
|
|
{
|
|
tuple_percent = (double) tuple_len *100.0 / table_len;
|
|
dead_tuple_percent = (double) dead_tuple_len *100.0 / table_len;
|
|
free_percent = (double) free_space *100.0 / table_len;
|
|
}
|
|
|
|
elog(DEBUG3, "physical length: %.2fMB live tuples: %.0f (%.2fMB, %.2f%%) dead tuples: %.0f (%.2fMB, %.2f%%) free/reusable space: %.2fMB (%.2f%%) overhead: %.2f%%",
|
|
|
|
table_len / (1024 * 1024), /* physical length in MB */
|
|
|
|
(double) tuple_count, /* number of live tuples */
|
|
(double) tuple_len / (1024 * 1024), /* live tuples in MB */
|
|
tuple_percent, /* live tuples in % */
|
|
|
|
(double) dead_tuple_count, /* number of dead tuples */
|
|
(double) dead_tuple_len / (1024 * 1024), /* dead tuples in MB */
|
|
dead_tuple_percent, /* dead tuples in % */
|
|
|
|
(double) free_space / (1024 * 1024), /* free/available space in
|
|
* MB */
|
|
|
|
free_percent, /* free/available space in % */
|
|
|
|
/* overhead in % */
|
|
(nblocks == 0) ? 0.0 : 100.0
|
|
- tuple_percent
|
|
- dead_tuple_percent
|
|
- free_percent);
|
|
|
|
PG_RETURN_FLOAT8(dead_tuple_percent);
|
|
}
|