diff --git a/src/backend/optimizer/util/inherit.c b/src/backend/optimizer/util/inherit.c
index 00b65ca305..f9d3ff1e7a 100644
--- a/src/backend/optimizer/util/inherit.c
+++ b/src/backend/optimizer/util/inherit.c
@@ -457,7 +457,8 @@ expand_single_inheritance_child(PlannerInfo *root, RangeTblEntry *parentrte,
 								Index *childRTindex_p)
 {
 	Query	   *parse = root->parse;
-	Oid			parentOID = RelationGetRelid(parentrel);
+	Oid			parentOID PG_USED_FOR_ASSERTS_ONLY =
+		RelationGetRelid(parentrel);
 	Oid			childOID = RelationGetRelid(childrel);
 	RangeTblEntry *childrte;
 	Index		childRTindex;