diff options
Diffstat (limited to 'src/backend/commands/trigger.c')
| -rw-r--r-- | src/backend/commands/trigger.c | 45 |
1 files changed, 44 insertions, 1 deletions
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c index 4b9d5efea98..9d2b2b64e98 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 - * $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.159.2.2 2006/01/12 21:49:31 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.159.2.3 2008/05/27 21:14:00 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -2365,6 +2365,49 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt) deferredTriggers->deftrig_events_imm = NULL; } +/* ---------- + * AfterTriggerPendingOnRel() + * Test to see if there are any pending after-trigger events for rel. + * + * This is used by TRUNCATE, CLUSTER, ALTER TABLE, etc to detect whether + * it is unsafe to perform major surgery on a relation. Note that only + * local pending events are examined. We assume that having exclusive lock + * on a rel guarantees there are no unserviced events in other backends --- + * but having a lock does not prevent there being such events in our own. + * + * In some scenarios it'd be reasonable to remove pending events (more + * specifically, mark them DONE by the current subxact) but without a lot + * of knowledge of the trigger semantics we can't do this in general. + * ---------- + */ +bool +AfterTriggerPendingOnRel(Oid relid) +{ + DeferredTriggerEvent event; + + /* No-op if we aren't in a transaction. (Shouldn't happen?) */ + if (deferredTriggers == NULL) + return false; + + /* Scan queued events */ + for (event = deferredTriggers->deftrig_events; + event != NULL; + event = event->dte_next) + { + /* + * We can ignore completed events. + */ + if (event->dte_event & (TRIGGER_DEFERRED_DONE | + TRIGGER_DEFERRED_CANCELED)) + continue; + + if (event->dte_relid == relid) + return true; + } + + return false; +} + /* ---------- * DeferredTriggerSaveEvent() |