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Add ALTER TABLE ENABLE/DISABLE TRIGGER commands. Change pg_dump to

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use these instead of its previous hack of changing pg_class.reltriggers.
Documentation is lacking, will add that later.
Patch by Satoshi Nagayasu, review and some extra work by Tom Lane.
This commit is contained in:
Tom Lane
2005-08-23 22:40:47 +00:00
parent d086da4bb1
commit 188c7c8ccf
9 changed files with 255 additions and 56 deletions
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110
src/backend/commands/trigger.c
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@ -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.
*