diff options
Diffstat (limited to 'src/backend/commands/trigger.c')
| -rw-r--r-- | src/backend/commands/trigger.c | 110 |
1 files changed, 109 insertions, 1 deletions
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c index 562f676f4b8..b1d2f4ce0db 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 1.192 2005/08/20 00:39:54 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.193 2005/08/23 22:40:08 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -712,6 +712,114 @@ renametrig(Oid relid, heap_close(targetrel, NoLock); } + +/* + * EnableDisableTrigger() + * + * Called by ALTER TABLE ENABLE/DISABLE TRIGGER + * to change 'tgenabled' flag for the specified trigger(s) + * + * rel: relation to process (caller must hold suitable lock on it) + * tgname: trigger to process, or NULL to scan all triggers + * enable: new value for tgenabled flag + * skip_system: if true, skip "system" triggers (constraint triggers) + * + * Caller should have checked permissions for the table; here we also + * enforce that superuser privilege is required to alter the state of + * system triggers + */ +void +EnableDisableTrigger(Relation rel, const char *tgname, + bool enable, bool skip_system) +{ + Relation tgrel; + int nkeys; + ScanKeyData keys[2]; + SysScanDesc tgscan; + HeapTuple tuple; + bool found; + bool changed; + + /* Scan the relevant entries in pg_triggers */ + tgrel = heap_open(TriggerRelationId, RowExclusiveLock); + + ScanKeyInit(&keys[0], + Anum_pg_trigger_tgrelid, + BTEqualStrategyNumber, F_OIDEQ, + ObjectIdGetDatum(RelationGetRelid(rel))); + if (tgname) + { + ScanKeyInit(&keys[1], + Anum_pg_trigger_tgname, + BTEqualStrategyNumber, F_NAMEEQ, + CStringGetDatum(tgname)); + nkeys = 2; + } + else + nkeys = 1; + + tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true, + SnapshotNow, nkeys, keys); + + found = changed = false; + + while (HeapTupleIsValid(tuple = systable_getnext(tgscan))) + { + Form_pg_trigger oldtrig = (Form_pg_trigger) GETSTRUCT(tuple); + + if (oldtrig->tgisconstraint) + { + /* system trigger ... ok to process? */ + if (skip_system) + continue; + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("permission denied: \"%s\" is a system trigger", + NameStr(oldtrig->tgname)))); + } + + found = true; + + if (oldtrig->tgenabled != enable) + { + /* need to change this one ... make a copy to scribble on */ + HeapTuple newtup = heap_copytuple(tuple); + Form_pg_trigger newtrig = (Form_pg_trigger) GETSTRUCT(newtup); + + newtrig->tgenabled = enable; + + simple_heap_update(tgrel, &newtup->t_self, newtup); + + /* Keep catalog indexes current */ + CatalogUpdateIndexes(tgrel, newtup); + + heap_freetuple(newtup); + + changed = true; + } + } + + systable_endscan(tgscan); + + heap_close(tgrel, RowExclusiveLock); + + if (tgname && !found) + ereport(ERROR, + (errcode(ERRCODE_UNDEFINED_OBJECT), + errmsg("trigger \"%s\" for table \"%s\" does not exist", + tgname, RelationGetRelationName(rel)))); + + /* + * If we changed anything, broadcast a SI inval message to force each + * backend (including our own!) to rebuild relation's relcache entry. + * Otherwise they will fail to apply the change promptly. + */ + if (changed) + CacheInvalidateRelcache(rel); +} + + /* * Build trigger data to attach to the given relcache entry. * |