diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 79e0b1f..6485fc4 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -951,7 +951,11 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 	 * if no such tuple exists, return NULL
 	 */
 	if (!HeapTupleIsValid(pg_class_tuple))
+	{
+		if(RelationIsValid(pg_class_relation))
+			heap_close(pg_class_relation, AccessShareLock);
 		return NULL;
+	}
 
 	/*
 	 * get information from the pg_class_tuple