Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commitb2a2f4c

Browse files
committed
Force pg_database updates out to disk immediately after ALTER DATABASE;
this is to avoid scenarios where incoming backends find no live copiesof a database's row because the only live copy is in an as-yet-unwrittenshared buffer, which they can't see. Also, use FlushRelationBuffers()for forcing out pg_database, instead of the much more expensive BufferSync().There's no need to write out pages belonging to other relations.
1 parentc36496a commitb2a2f4c

File tree

1 file changed

+47
-19
lines changed

1 file changed

+47
-19
lines changed

‎src/backend/commands/dbcommands.c‎

Lines changed: 47 additions & 19 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
*
1010
*
1111
* IDENTIFICATION
12-
* $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.146 2004/10/28 00:39:58 tgl Exp $
12+
* $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.147 2004/11/18 01:14:26 tgl Exp $
1313
*
1414
*-------------------------------------------------------------------------
1515
*/
@@ -330,7 +330,7 @@ createdb(const CreatedbStmt *stmt)
330330
/*
331331
* Force dirty buffers out to disk, to ensure source database is
332332
* up-to-date for the copy. (We really only need to flush buffers for
333-
* the source database...)
333+
* the source database, but bufmgr.c provides no API for that.)
334334
*/
335335
BufferSync(-1,-1);
336336

@@ -497,15 +497,15 @@ createdb(const CreatedbStmt *stmt)
497497
/* Update indexes */
498498
CatalogUpdateIndexes(pg_database_rel,tuple);
499499

500-
/* Close pg_database, but keep lock till commit */
501-
heap_close(pg_database_rel,NoLock);
502-
503500
/*
504501
* Force dirty buffers out to disk, so that newly-connecting backends
505502
* will see the new database in pg_database right away. (They'll see
506503
* an uncommitted tuple, but they don't care; see GetRawDatabaseInfo.)
507504
*/
508-
BufferSync(-1,-1);
505+
FlushRelationBuffers(pg_database_rel,MaxBlockNumber);
506+
507+
/* Close pg_database, but keep exclusive lock till commit */
508+
heap_close(pg_database_rel,NoLock);
509509
}
510510

511511

@@ -607,12 +607,6 @@ dropdb(const char *dbname)
607607
*/
608608
DeleteComments(db_id,RelationGetRelid(pgdbrel),0);
609609

610-
/*
611-
* Close pg_database, but keep exclusive lock till commit to ensure
612-
* that any new backend scanning pg_database will see the tuple dead.
613-
*/
614-
heap_close(pgdbrel,NoLock);
615-
616610
/*
617611
* Drop pages for this database that are in the shared buffer cache.
618612
* This is important to ensure that no remaining backend tries to
@@ -644,7 +638,10 @@ dropdb(const char *dbname)
644638
* (They'll see an uncommitted deletion, but they don't care; see
645639
* GetRawDatabaseInfo.)
646640
*/
647-
BufferSync(-1,-1);
641+
FlushRelationBuffers(pgdbrel,MaxBlockNumber);
642+
643+
/* Close pg_database, but keep exclusive lock till commit */
644+
heap_close(pgdbrel,NoLock);
648645
}
649646

650647

@@ -733,15 +730,17 @@ RenameDatabase(const char *oldname, const char *newname)
733730
CatalogUpdateIndexes(rel,newtup);
734731

735732
systable_endscan(scan);
736-
heap_close(rel,NoLock);
737733

738734
/*
739735
* Force dirty buffers out to disk, so that newly-connecting backends
740736
* will see the renamed database in pg_database right away. (They'll
741737
* see an uncommitted tuple, but they don't care; see
742738
* GetRawDatabaseInfo.)
743739
*/
744-
BufferSync(-1,-1);
740+
FlushRelationBuffers(rel,MaxBlockNumber);
741+
742+
/* Close pg_database, but keep exclusive lock till commit */
743+
heap_close(rel,NoLock);
745744
}
746745

747746

@@ -763,7 +762,10 @@ AlterDatabaseSet(AlterDatabaseSetStmt *stmt)
763762

764763
valuestr=flatten_set_variable_args(stmt->variable,stmt->value);
765764

766-
rel=heap_openr(DatabaseRelationName,RowExclusiveLock);
765+
/*
766+
* We need AccessExclusiveLock so we can safely do FlushRelationBuffers.
767+
*/
768+
rel=heap_openr(DatabaseRelationName,AccessExclusiveLock);
767769
ScanKeyInit(&scankey,
768770
Anum_pg_database_datname,
769771
BTEqualStrategyNumber,F_NAMEEQ,
@@ -821,6 +823,16 @@ AlterDatabaseSet(AlterDatabaseSetStmt *stmt)
821823
CatalogUpdateIndexes(rel,newtuple);
822824

823825
systable_endscan(scan);
826+
827+
/*
828+
* Force dirty buffers out to disk, so that newly-connecting backends
829+
* will see the altered row in pg_database right away. (They'll
830+
* see an uncommitted tuple, but they don't care; see
831+
* GetRawDatabaseInfo.)
832+
*/
833+
FlushRelationBuffers(rel,MaxBlockNumber);
834+
835+
/* Close pg_database, but keep exclusive lock till commit */
824836
heap_close(rel,NoLock);
825837
}
826838

@@ -837,7 +849,10 @@ AlterDatabaseOwner(const char *dbname, AclId newOwnerSysId)
837849
SysScanDescscan;
838850
Form_pg_databasedatForm;
839851

840-
rel=heap_openr(DatabaseRelationName,RowExclusiveLock);
852+
/*
853+
* We need AccessExclusiveLock so we can safely do FlushRelationBuffers.
854+
*/
855+
rel=heap_openr(DatabaseRelationName,AccessExclusiveLock);
841856
ScanKeyInit(&scankey,
842857
Anum_pg_database_datname,
843858
BTEqualStrategyNumber,F_NAMEEQ,
@@ -901,9 +916,22 @@ AlterDatabaseOwner(const char *dbname, AclId newOwnerSysId)
901916
CatalogUpdateIndexes(rel,newtuple);
902917

903918
heap_freetuple(newtuple);
919+
920+
/* must release buffer pins before FlushRelationBuffers */
921+
systable_endscan(scan);
922+
923+
/*
924+
* Force dirty buffers out to disk, so that newly-connecting backends
925+
* will see the altered row in pg_database right away. (They'll
926+
* see an uncommitted tuple, but they don't care; see
927+
* GetRawDatabaseInfo.)
928+
*/
929+
FlushRelationBuffers(rel,MaxBlockNumber);
904930
}
931+
else
932+
systable_endscan(scan);
905933

906-
systable_endscan(scan);
934+
/* Close pg_database, but keep exclusive lock till commit */
907935
heap_close(rel,NoLock);
908936
}
909937

@@ -1176,7 +1204,7 @@ dbase_redo(XLogRecPtr lsn, XLogRecord *record)
11761204
/*
11771205
* Force dirty buffers out to disk, to ensure source database is
11781206
* up-to-date for the copy. (We really only need to flush buffers for
1179-
* the source database...)
1207+
* the source database, but bufmgr.c provides no API for that.)
11801208
*/
11811209
BufferSync(-1,-1);
11821210

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp