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Perform transaction cleanup operations in a less ad-hoc, more 

principled order; in particular ensure that all shared resources
are released before we release transaction locks.  The code used
to release locks before buffer pins, which might explain an ancient
note I have about a bufmgr assertion failure I'd seen once several
years ago, and been unable to reproduce since.  (Theory: someone
trying to drop a relation might be able to reach FlushRelationBuffers
before the last user of the relation had gotten around to dropping
his buffer pins.)
This commit is contained in:
Tom Lane 2002-10-22 22:44:36 +00:00
parent 68c8bce69e
commit 30963fc200
1 changed files with 26 additions and 14 deletions
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40
src/backend/access/transam/xact.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.134 2002/10/21 22:06:18 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.135 2002/10/22 22:44:36 tgl Exp $
*
* NOTES
* Transaction aborts can now occur two ways:
@ -1005,9 +1005,20 @@ CommitTransaction(void)
* This is all post-commit cleanup. Note that if an error is raised
* here, it's too late to abort the transaction. This should be just
* noncritical resource releasing.
*
* The ordering of operations is not entirely random. The idea is:
* release resources visible to other backends (eg, files, buffer pins);
* then release locks; then release backend-local resources. We want
* to release locks at the point where any backend waiting for us will
* see our transaction as being fully cleaned up.
*/
smgrDoPendingDeletes(true);
AtCommit_Cache();
AtEOXact_Buffers(true);
/* smgrcommit already done */
AtCommit_Locks();
AtEOXact_GUC(true);
AtEOXact_SPI();
@ -1016,15 +1027,10 @@ CommitTransaction(void)
AtEOXact_nbtree();
AtEOXact_rtree();
AtEOXact_Namespace(true);
AtCommit_Cache();
AtCommit_Locks();
AtEOXact_CatCache(true);
AtCommit_Memory();
AtEOXact_Buffers(true);
AtEOXact_Files();
/* Count transaction commit in statistics collector */
pgstat_count_xact_commit();
AtCommit_Memory();
/*
* done with commit processing, set current transaction state back to
@ -1078,6 +1084,9 @@ AbortTransaction(void)
*/
s->state = TRANS_ABORT;
/* Make sure we are in a valid memory context */
AtAbort_Memory();
/*
* Reset user id which might have been changed transiently
*/
@ -1109,7 +1118,17 @@ AbortTransaction(void)
LWLockRelease(SInvalLock);
}
/*
* Post-abort cleanup. See notes in CommitTransaction() concerning
* ordering.
*/
smgrDoPendingDeletes(false);
AtAbort_Cache();
AtEOXact_Buffers(false);
smgrabort();
AtAbort_Locks();
AtEOXact_GUC(false);
AtEOXact_SPI();
@ -1118,15 +1137,8 @@ AbortTransaction(void)
AtEOXact_nbtree();
AtEOXact_rtree();
AtEOXact_Namespace(false);
AtAbort_Cache();
AtEOXact_CatCache(false);
AtAbort_Memory();
AtEOXact_Buffers(false);
smgrabort();
AtEOXact_Files();
AtAbort_Locks();
/* Count transaction abort in statistics collector */
pgstat_count_xact_rollback();
/*