Record parents of triggers

This let us get rid of a recently introduced ugly hack (commit
1fa846f1c9af).

Author: Álvaro Herrera
Reviewed-by: Amit Langote, Tom Lane
Discussion: https://postgr.es/m/20200217215641.GA29784@alvherre.pgsql

1 files changed, 5 insertions, 54 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index b7c8d663fc4..02a7c04fdb7 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -16448,54 +16448,6 @@ out:
 }
 
 /*
- * isPartitionTrigger
- *		Subroutine for CloneRowTriggersToPartition: determine whether
- *		the given trigger has been cloned from another one.
- *
- * We use pg_depend as a proxy for this, since we don't have any direct
- * evidence.  This is an ugly hack to cope with a catalog deficiency.
- * Keep away from children.  Do not stare with naked eyes.  Do not propagate.
- */
-static bool
-isPartitionTrigger(Oid trigger_oid)
-{
-	Relation	pg_depend;
-	ScanKeyData key[2];
-	SysScanDesc scan;
-	HeapTuple	tup;
-	bool		found = false;
-
-	pg_depend = table_open(DependRelationId, AccessShareLock);
-
-	ScanKeyInit(&key[0], Anum_pg_depend_classid,
-				BTEqualStrategyNumber,
-				F_OIDEQ,
-				ObjectIdGetDatum(TriggerRelationId));
-	ScanKeyInit(&key[1], Anum_pg_depend_objid,
-				BTEqualStrategyNumber,
-				F_OIDEQ,
-				ObjectIdGetDatum(trigger_oid));
-
-	scan = systable_beginscan(pg_depend, DependDependerIndexId,
-							  true, NULL, 2, key);
-	while ((tup = systable_getnext(scan)) != NULL)
-	{
-		Form_pg_depend dep = (Form_pg_depend) GETSTRUCT(tup);
-
-		if (dep->refclassid == TriggerRelationId)
-		{
-			found = true;
-			break;
-		}
-	}
-
-	systable_endscan(scan);
-	table_close(pg_depend, AccessShareLock);
-
-	return found;
-}
-
-/*
  * CloneRowTriggersToPartition
  *		subroutine for ATExecAttachPartition/DefineRelation to create row
  *		triggers on partitions
@@ -16537,11 +16489,10 @@ CloneRowTriggersToPartition(Relation parent, Relation partition)
 
 		/*
 		 * Internal triggers require careful examination.  Ideally, we don't
-		 * clone them.
-		 *
-		 * However, if our parent is a partitioned relation, there might be
-		 * internal triggers that need cloning.  In that case, we must skip
-		 * clone it if the trigger on parent depends on another trigger.
+		 * clone them.  However, if our parent is itself a partition, there
+		 * might be internal triggers that must not be skipped; for example,
+		 * triggers on our parent that are in turn clones from its parent (our
+		 * grandparent) are marked internal, yet they are to be cloned.
 		 *
 		 * Note we dare not verify that the other trigger belongs to an
 		 * ancestor relation of our parent, because that creates deadlock
@@ -16549,7 +16500,7 @@ CloneRowTriggersToPartition(Relation parent, Relation partition)
 		 */
 		if (trigForm->tgisinternal &&
 			(!parent->rd_rel->relispartition ||
-			 !isPartitionTrigger(trigForm->oid)))
+			 !OidIsValid(trigForm->tgparentid)))
 			continue;
 
 		/*