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133 lines
3.7 KiB
C
133 lines
3.7 KiB
C
/*
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* $Header: /cvsroot/pgsql/contrib/pgstattuple/pgstattuple.c,v 1.2 2001/10/25 05:49:20 momjian Exp $
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*
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* Copyright (c) 2001 Tatsuo Ishii
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*
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* Permission to use, copy, modify, and distribute this software and
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* its documentation for any purpose, without fee, and without a
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* written agreement is hereby granted, provided that the above
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* copyright notice and this paragraph and the following two
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* paragraphs appear in all copies.
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*
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
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* INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
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* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
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* DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
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* IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
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* SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*/
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#include "postgres.h"
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#include "fmgr.h"
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#include "access/heapam.h"
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#include "access/transam.h"
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PG_FUNCTION_INFO_V1(pgstattuple);
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extern Datum pgstattuple(PG_FUNCTION_ARGS);
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/* ----------
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* pgstattuple:
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* returns the percentage of dead tuples
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*
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* C FUNCTION definition
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* pgstattuple(NAME) returns FLOAT8
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* ----------
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*/
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Datum
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pgstattuple(PG_FUNCTION_ARGS)
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{
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Name p = PG_GETARG_NAME(0);
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Relation rel;
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HeapScanDesc scan;
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HeapTuple tuple;
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BlockNumber nblocks;
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BlockNumber block = InvalidBlockNumber;
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double table_len;
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uint64 tuple_len = 0;
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uint64 dead_tuple_len = 0;
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uint32 tuple_count = 0;
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uint32 dead_tuple_count = 0;
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double tuple_percent;
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double dead_tuple_percent;
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Buffer buffer = InvalidBuffer;
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uint64 free_space = 0; /* free/reusable space in bytes */
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double free_percent; /* free/reusable space in % */
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rel = heap_openr(NameStr(*p), NoLock);
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nblocks = RelationGetNumberOfBlocks(rel);
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scan = heap_beginscan(rel, false, SnapshotAny, 0, NULL);
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while ((tuple = heap_getnext(scan, 0)))
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{
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if (HeapTupleSatisfiesNow(tuple->t_data))
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{
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tuple_len += tuple->t_len;
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tuple_count++;
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}
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else
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{
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dead_tuple_len += tuple->t_len;
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dead_tuple_count++;
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}
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if (!BlockNumberIsValid(block) ||
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block != BlockIdGetBlockNumber(&tuple->t_self.ip_blkid))
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{
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block = BlockIdGetBlockNumber(&tuple->t_self.ip_blkid);
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buffer = ReadBuffer(rel, block);
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free_space += PageGetFreeSpace((Page) BufferGetPage(buffer));
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ReleaseBuffer(buffer);
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}
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}
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heap_endscan(scan);
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heap_close(rel, NoLock);
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table_len = (double) nblocks *BLCKSZ;
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if (nblocks == 0)
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{
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tuple_percent = 0.0;
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dead_tuple_percent = 0.0;
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free_percent = 0.0;
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}
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else
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{
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tuple_percent = (double) tuple_len *100.0 / table_len;
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dead_tuple_percent = (double) dead_tuple_len *100.0 / table_len;
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free_percent = (double) free_space *100.0 / table_len;
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}
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elog(NOTICE, "physical length: %.2fMB live tuples: %u (%.2fMB, %.2f%%) dead tuples: %u (%.2fMB, %.2f%%) free/reusable space: %.2fMB (%.2f%%) overhead: %.2f%%",
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table_len / 1024 / 1024, /* phsical length in MB */
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tuple_count, /* number of live tuples */
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(double) tuple_len / 1024 / 1024, /* live tuples in MB */
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tuple_percent, /* live tuples in % */
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dead_tuple_count, /* number of dead tuples */
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(double) dead_tuple_len / 1024 / 1024, /* dead tuples in MB */
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dead_tuple_percent, /* dead tuples in % */
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(double) free_space / 1024 / 1024, /* free/available space in
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* MB */
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free_percent, /* free/available space in % */
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/* overhead in % */
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(nblocks == 0) ? 0.0 : 100.0
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- tuple_percent
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- dead_tuple_percent
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- free_percent);
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PG_RETURN_FLOAT8(dead_tuple_percent);
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}
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