diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c
index 2f4fea241a..0311c0ff32 100644
--- a/src/backend/optimizer/path/pathkeys.c
+++ b/src/backend/optimizer/path/pathkeys.c
@@ -1288,6 +1288,8 @@ find_mergeclauses_for_outer_pathkeys(PlannerInfo *root,
 		 * add them to result list.
 		 */
 		mergeclauses = list_concat(mergeclauses, matched_restrictinfos);
+
+		list_free(matched_restrictinfos);
 	}
 
 	return mergeclauses;