From d5d0a67b22bfdbdac254a059b2d2a0a9547fc285 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 24 Jan 2010 21:49:58 +0000 Subject: [PATCH] Fix assorted core dumps and Assert failures that could occur during AbortTransaction or AbortSubTransaction, when trying to clean up after an error that prevented (sub)transaction start from completing: * access to TopTransactionResourceOwner that might not exist * assert failure in AtEOXact_GUC, if AtStart_GUC not called yet * assert failure or core dump in AfterTriggerEndSubXact, if AfterTriggerBeginSubXact not called yet Per testing by injecting elog(ERROR) at successive steps in StartTransaction and StartSubTransaction. It's not clear whether all of these cases could really occur in the field, but at least one of them is easily exposed by simple stress testing, as per my accidental discovery yesterday. --- src/backend/access/transam/xact.c | 57 ++++++++++++++++--------------- src/backend/commands/trigger.c | 15 +++++--- src/backend/utils/misc/guc.c | 11 ++++-- 3 files changed, 50 insertions(+), 33 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index 55a46cef668..33a862c8ef6 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -10,7 +10,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.215.2.6 2009/12/09 21:58:41 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.215.2.7 2010/01/24 21:49:58 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1919,35 +1919,38 @@ AbortTransaction(void) /* * Post-abort cleanup. See notes in CommitTransaction() concerning - * ordering. + * ordering. We can skip all of it if the transaction failed before + * creating a resource owner. */ + if (TopTransactionResourceOwner != NULL) + { + CallXactCallbacks(XACT_EVENT_ABORT); - CallXactCallbacks(XACT_EVENT_ABORT); + ResourceOwnerRelease(TopTransactionResourceOwner, + RESOURCE_RELEASE_BEFORE_LOCKS, + false, true); + AtEOXact_Buffers(false); + AtEOXact_RelationCache(false); + AtEOXact_Inval(false); + smgrDoPendingDeletes(false); + AtEOXact_MultiXact(); + ResourceOwnerRelease(TopTransactionResourceOwner, + RESOURCE_RELEASE_LOCKS, + false, true); + ResourceOwnerRelease(TopTransactionResourceOwner, + RESOURCE_RELEASE_AFTER_LOCKS, + false, true); + AtEOXact_CatCache(false); - ResourceOwnerRelease(TopTransactionResourceOwner, - RESOURCE_RELEASE_BEFORE_LOCKS, - false, true); - AtEOXact_Buffers(false); - AtEOXact_RelationCache(false); - AtEOXact_Inval(false); - smgrDoPendingDeletes(false); - AtEOXact_MultiXact(); - ResourceOwnerRelease(TopTransactionResourceOwner, - RESOURCE_RELEASE_LOCKS, - false, true); - ResourceOwnerRelease(TopTransactionResourceOwner, - RESOURCE_RELEASE_AFTER_LOCKS, - false, true); - AtEOXact_CatCache(false); - - AtEOXact_GUC(false, 1); - AtEOXact_SPI(false); - AtEOXact_on_commit_actions(false); - AtEOXact_Namespace(false); - smgrabort(); - AtEOXact_Files(); - AtEOXact_HashTables(false); - pgstat_count_xact_rollback(); + AtEOXact_GUC(false, 1); + AtEOXact_SPI(false); + AtEOXact_on_commit_actions(false); + AtEOXact_Namespace(false); + smgrabort(); + AtEOXact_Files(); + AtEOXact_HashTables(false); + pgstat_count_xact_rollback(); + } /* * State remains TRANS_ABORT until CleanupTransaction(). diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c index 5c97e5feabe..b82125eb337 100644 --- a/src/backend/commands/trigger.c +++ b/src/backend/commands/trigger.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.195.2.7 2009/10/27 20:14:56 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.195.2.8 2010/01/24 21:49:58 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -2742,10 +2742,9 @@ AfterTriggerEndSubXact(bool isCommit) /* * Pop the prior state if needed. */ - Assert(my_level < afterTriggers->maxtransdepth); - if (isCommit) { + Assert(my_level < afterTriggers->maxtransdepth); /* If we saved a prior state, we don't need it anymore */ state = afterTriggers->state_stack[my_level]; if (state != NULL) @@ -2758,7 +2757,15 @@ AfterTriggerEndSubXact(bool isCommit) else { /* - * Aborting --- restore the pointers from the stacks. + * Aborting. It is possible subxact start failed before calling + * AfterTriggerBeginSubXact, in which case we mustn't risk touching + * stack levels that aren't there. + */ + if (my_level >= afterTriggers->maxtransdepth) + return; + + /* + * Restore the pointers from the stacks. */ afterTriggers->events = afterTriggers->events_stack[my_level]; afterTriggers->query_depth = afterTriggers->depth_stack[my_level]; diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 751e7921512..ed734975854 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -10,7 +10,7 @@ * Written by Peter Eisentraut . * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.299.2.6 2009/12/09 21:58:43 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.299.2.7 2010/01/24 21:49:58 tgl Exp $ * *-------------------------------------------------------------------- */ @@ -3109,7 +3109,14 @@ AtEOXact_GUC(bool isCommit, int nestLevel) { int i; - Assert(nestLevel > 0 && nestLevel <= GUCNestLevel); + /* + * Note: it's possible to get here with GUCNestLevel == nestLevel-1 during + * abort, if there is a failure during transaction start before + * AtStart_GUC is called. + */ + Assert(nestLevel > 0 && + (nestLevel <= GUCNestLevel || + (nestLevel == GUCNestLevel + 1 && !isCommit))); /* Quick exit if nothing's changed in this transaction */ if (!guc_dirty)