diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index b223972..fc0f08e 100644
*** a/src/backend/optimizer/plan/planner.c
--- b/src/backend/optimizer/plan/planner.c
*************** inheritance_planner(PlannerInfo *root)
*** 1307,1312 ****
--- 1307,1313 ----
  		RangeTblEntry *child_rte;
  		RelOptInfo *sub_final_rel;
  		Path	   *subpath;
+ 		ListCell   *lc2;
  
  		/* append_rel_list contains all append rels; ignore others */
  		if (!bms_is_member(appinfo->parent_relid, parent_relids))
*************** inheritance_planner(PlannerInfo *root)
*** 1416,1439 ****
  		 * want to copy items that actually contain such references; the rest
  		 * can just get linked into the subroot's append_rel_list.
  		 *
! 		 * If we know there are no such references, we can just use the outer
! 		 * append_rel_list unmodified.
  		 */
! 		if (modifiableARIindexes != NULL)
  		{
! 			ListCell   *lc2;
  
! 			subroot->append_rel_list = NIL;
! 			foreach(lc2, parent_root->append_rel_list)
! 			{
! 				AppendRelInfo *appinfo2 = lfirst_node(AppendRelInfo, lc2);
  
! 				if (bms_is_member(appinfo2->child_relid, modifiableARIindexes))
! 					appinfo2 = copyObject(appinfo2);
  
! 				subroot->append_rel_list = lappend(subroot->append_rel_list,
! 												   appinfo2);
! 			}
  		}
  
  		/*
--- 1417,1441 ----
  		 * want to copy items that actually contain such references; the rest
  		 * can just get linked into the subroot's append_rel_list.
  		 *
! 		 * While we're at it, drop the AppendRelInfo items that link the
! 		 * current parent to its children from the subquery's append_rel_list.
! 		 * Those items are irrelevant for the subquery, so keeping them just
! 		 * wastes cycles during subquery planning, and could confuse code
! 		 * elsewhere.
  		 */
! 		subroot->append_rel_list = NIL;
! 		foreach(lc2, parent_root->append_rel_list)
  		{
! 			AppendRelInfo *appinfo2 = lfirst_node(AppendRelInfo, lc2);
  
! 			if (appinfo2->parent_relid == appinfo->parent_relid)
! 				continue;
  
! 			if (bms_is_member(appinfo2->child_relid, modifiableARIindexes))
! 				appinfo2 = copyObject(appinfo2);
  
! 			subroot->append_rel_list = lappend(subroot->append_rel_list,
! 											   appinfo2);
  		}
  
  		/*