From 2c31cac22178d904ee108b77f316886d1e2f6288 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Fri, 3 Apr 2020 22:43:26 -0500
Subject: [PATCH] WIP: fix detaching tables with inherited triggers

---
 src/backend/commands/tablecmds.c | 33 ++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 037d457c3d..10a60e158f 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -16797,6 +16797,39 @@ ATExecDetachPartition(Relation rel, RangeVar *name)
 	}
 	table_close(classRel, RowExclusiveLock);
 
+	/* detach triggers too */
+	{
+		/* XXX: relcache.c */
+		ScanKeyData skey;
+		SysScanDesc	scan;
+		HeapTuple	trigtup;
+		Relation	tgrel = table_open(TriggerRelationId, RowExclusiveLock);
+
+		ScanKeyInit(&skey, Anum_pg_trigger_tgrelid, BTEqualStrategyNumber,
+				F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(partRel)));
+
+		scan = systable_beginscan(tgrel, TriggerRelidNameIndexId,
+				true, NULL, 1, &skey);
+
+		while (HeapTupleIsValid(trigtup = systable_getnext(scan)))
+		{
+			Form_pg_trigger pg_trigger;
+			trigtup = heap_copytuple(trigtup);  /* need a modifiable copy */
+			pg_trigger = (Form_pg_trigger) GETSTRUCT(trigtup);
+			/* Set the trigger's parent to Invalid */
+			if (!OidIsValid(pg_trigger->tgparentid))
+				continue;
+			if (!pg_trigger->tgisinternal)
+				continue;
+			pg_trigger->tgparentid = InvalidOid;
+			pg_trigger->tgisinternal = false;
+			CatalogTupleUpdate(tgrel, &trigtup->t_self, trigtup);
+			heap_freetuple(trigtup);
+		}
+		systable_endscan(scan);
+		table_close(tgrel, RowExclusiveLock);
+	}
+
 	/*
 	 * Detach any foreign keys that are inherited.  This includes creating
 	 * additional action triggers.
-- 
2.17.0

