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Arrange for VACUUM to delete the init file that relcache.c uses

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to save a little bit of backend startup time.  This way, the first
backend started after a VACUUM will rebuild the init file with up-to-date
statistics for the critical system indexes.
This commit is contained in:
Tom Lane 1999-05-01 19:09:46 +00:00
parent f7d25d2ab6
commit 87d95ca04d
3 changed files with 41 additions and 20 deletions
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18
src/backend/commands/vacuum.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.99 1999/04/12 16:56:36 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.100 1999/05/01 19:09:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -46,6 +46,7 @@
#include "utils/inval.h"
#include "utils/mcxt.h"
#include "utils/portal.h"
#include "utils/relcache.h"
#include "utils/syscache.h"
#ifndef HAVE_GETRUSAGE
@ -219,7 +220,20 @@ vc_init()
static void
vc_shutdown()
{
/* on entry, not in a transaction */
/* on entry, we are not in a transaction */
/* Flush the init file that relcache.c uses to save startup time.
* The next backend startup will rebuild the init file with up-to-date
* information from pg_class. This lets the optimizer see the stats that
* we've collected for certain critical system indexes. See relcache.c
* for more details.
*
* Ignore any failure to unlink the file, since it might not be there
* if no backend has been started since the last vacuum...
*/
unlink(RELCACHE_INIT_FILENAME);
/* remove the vacuum cleaner lock file */
if (unlink("pg_vlock") < 0)
elog(ERROR, "vacuum: can't destroy lock file!");

35
src/backend/utils/cache/relcache.c vendored
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.59 1999/02/21 03:49:36 scrappy Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.60 1999/05/01 19:09:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -77,7 +77,6 @@
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/relcache.h"
#include "utils/relcache.h"
#include "utils/syscache.h"
@ -87,13 +86,6 @@ static Relation RelationNameCacheGetRelation(char *relationName);
static void init_irels(void);
static void write_irels(void);
/* ----------------
* defines
* ----------------
*/
#define private static
#define INIT_FILENAME "pg_internal.init"
/* ----------------
* externs
* ----------------
@ -1826,11 +1818,20 @@ RelCheckFetch(Relation relation)
* from an initialization file in the data/base/... directory.
*
* + If the initialization file isn't there, then we create the
* relation descriptor using sequential scans and write it to
* relation descriptors using sequential scans and write 'em to
* the initialization file for use by subsequent backends.
*
* This is complicated and interferes with system changes, but
* performance is so bad that we're willing to pay the tax.
* We could dispense with the initialization file and just build the
* critical reldescs the hard way on every backend startup, but that
* slows down backend startup noticeably if pg_class is large.
*
* As of v6.5, vacuum.c deletes the initialization file at completion
* of a VACUUM, so that it will be rebuilt at the next backend startup.
* This ensures that vacuum-collected stats for the system indexes
* will eventually get used by the optimizer --- otherwise the relcache
* entries for these indexes will show zero sizes forever, since the
* relcache entries are pinned in memory and will never be reloaded
* from pg_class.
*/
/* pg_attnumind, pg_classnameind, pg_classoidind */
@ -1852,9 +1853,9 @@ init_irels(void)
int relno;
#ifndef __CYGWIN32__
if ((fd = FileNameOpenFile(INIT_FILENAME, O_RDONLY, 0600)) < 0)
if ((fd = FileNameOpenFile(RELCACHE_INIT_FILENAME, O_RDONLY, 0600)) < 0)
#else
if ((fd = FileNameOpenFile(INIT_FILENAME, O_RDONLY | O_BINARY, 0600)) < 0)
if ((fd = FileNameOpenFile(RELCACHE_INIT_FILENAME, O_RDONLY | O_BINARY, 0600)) < 0)
#endif
{
write_irels();
@ -2017,12 +2018,12 @@ write_irels(void)
RelationBuildDescInfo bi;
#ifndef __CYGWIN32__
fd = FileNameOpenFile(INIT_FILENAME, O_WRONLY | O_CREAT | O_TRUNC, 0600);
fd = FileNameOpenFile(RELCACHE_INIT_FILENAME, O_WRONLY | O_CREAT | O_TRUNC, 0600);
#else
fd = FileNameOpenFile(INIT_FILENAME, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0600);
fd = FileNameOpenFile(RELCACHE_INIT_FILENAME, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0600);
#endif
if (fd < 0)
elog(FATAL, "cannot create init file %s", INIT_FILENAME);
elog(FATAL, "cannot create init file %s", RELCACHE_INIT_FILENAME);
FileSeek(fd, 0L, SEEK_SET);

8
src/include/utils/relcache.h
View File

@ -6,7 +6,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: relcache.h,v 1.11 1999/02/13 23:22:31 momjian Exp $
* $Id: relcache.h,v 1.12 1999/05/01 19:09:43 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -34,4 +34,10 @@ extern void RelationRegisterRelation(Relation relation);
extern void RelationPurgeLocalRelation(bool xactComitted);
extern void RelationInitialize(void);
/*
* both vacuum.c and relcache.c need to know the name of the relcache init file
*/
#define RELCACHE_INIT_FILENAME "pg_internal.init"
#endif /* RELCACHE_H */