diff options
Diffstat (limited to 'src/backend/commands/trigger.c')
| -rw-r--r-- | src/backend/commands/trigger.c | 52 |
1 files changed, 42 insertions, 10 deletions
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c index 0bc6f10cc79..627be4d5813 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 1.210.2.6 2008/10/25 03:32:51 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.210.2.7 2008/12/13 02:00:52 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -3181,19 +3181,51 @@ AfterTriggerSetState(ConstraintsSetStmt *stmt) if (!stmt->deferred) { AfterTriggerEventList *events = &afterTriggers->events; + Snapshot saveActiveSnapshot = ActiveSnapshot; - while (afterTriggerMarkEvents(events, NULL, true)) + /* PG_TRY to ensure previous ActiveSnapshot is restored on error */ + PG_TRY(); { - CommandId firing_id = afterTriggers->firing_counter++; + Snapshot mySnapshot = NULL; - /* - * We can delete fired events if we are at top transaction level, - * but we'd better not if inside a subtransaction, since the - * subtransaction could later get rolled back. - */ - afterTriggerInvokeEvents(-1, firing_id, NULL, - !IsSubTransaction()); + while (afterTriggerMarkEvents(events, NULL, true)) + { + CommandId firing_id = afterTriggers->firing_counter++; + + /* + * Make sure a snapshot has been established in case trigger + * functions need one. Note that we avoid setting a snapshot + * if we don't find at least one trigger that has to be fired + * now. This is so that BEGIN; SET CONSTRAINTS ...; SET + * TRANSACTION ISOLATION LEVEL SERIALIZABLE; ... works + * properly. (If we are at the start of a transaction it's + * not possible for any trigger events to be queued yet.) + */ + if (mySnapshot == NULL) + { + mySnapshot = CopySnapshot(GetTransactionSnapshot()); + ActiveSnapshot = mySnapshot; + } + + /* + * We can delete fired events if we are at top transaction level, + * but we'd better not if inside a subtransaction, since the + * subtransaction could later get rolled back. + */ + afterTriggerInvokeEvents(-1, firing_id, NULL, + !IsSubTransaction()); + } + + if (mySnapshot) + FreeSnapshot(mySnapshot); + } + PG_CATCH(); + { + ActiveSnapshot = saveActiveSnapshot; + PG_RE_THROW(); } + PG_END_TRY(); + ActiveSnapshot = saveActiveSnapshot; } } |