Pass the correct PlannerInfo to PlanForeignModify/PlanDirectModify.

Previously, we passed the toplevel PlannerInfo, but we actually want
to pass the relevant subroot.  One problem with passing the toplevel
PlannerInfo is that the FDW which wants to push down an UPDATE or
DELETE against a join won't find the relevant joinrel there.
As of commit 1bc0100d270e5bcc980a0629b8726a32a497e788, postgres_fdw
tries to do exactly this and can be made to fail an assertion as a
result.

It's possible that this should be regarded as a bug fix and
back-patched to earlier releases, but for lack of a test case that
fails in earlier releases, no back-patch for now.

Etsuro Fujita, reviewed by Amit Langote.

Discussion: http://postgr.es/m/5AF43E02.30000@lab.ntt.co.jp

1 files changed, 14 insertions, 10 deletions

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 0317763f43c..ca2e0527dbc 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -289,7 +289,7 @@ static ModifyTable *make_modifytable(PlannerInfo *root,
 				 CmdType operation, bool canSetTag,
 				 Index nominalRelation, List *partitioned_rels,
 				 bool partColsUpdated,
-				 List *resultRelations, List *subplans,
+				 List *resultRelations, List *subplans, List *subroots,
 				 List *withCheckOptionLists, List *returningLists,
 				 List *rowMarks, OnConflictExpr *onconflict, int epqParam);
 static GatherMerge *create_gather_merge_plan(PlannerInfo *root,
@@ -2484,6 +2484,7 @@ create_modifytable_plan(PlannerInfo *root, ModifyTablePath *best_path)
 							best_path->partColsUpdated,
 							best_path->resultRelations,
 							subplans,
+							best_path->subroots,
 							best_path->withCheckOptionLists,
 							best_path->returningLists,
 							best_path->rowMarks,
@@ -6558,7 +6559,7 @@ make_modifytable(PlannerInfo *root,
 				 CmdType operation, bool canSetTag,
 				 Index nominalRelation, List *partitioned_rels,
 				 bool partColsUpdated,
-				 List *resultRelations, List *subplans,
+				 List *resultRelations, List *subplans, List *subroots,
 				 List *withCheckOptionLists, List *returningLists,
 				 List *rowMarks, OnConflictExpr *onconflict, int epqParam)
 {
@@ -6566,9 +6567,11 @@ make_modifytable(PlannerInfo *root,
 	List	   *fdw_private_list;
 	Bitmapset  *direct_modify_plans;
 	ListCell   *lc;
+	ListCell   *lc2;
 	int			i;
 
 	Assert(list_length(resultRelations) == list_length(subplans));
+	Assert(list_length(resultRelations) == list_length(subroots));
 	Assert(withCheckOptionLists == NIL ||
 		   list_length(resultRelations) == list_length(withCheckOptionLists));
 	Assert(returningLists == NIL ||
@@ -6627,9 +6630,10 @@ make_modifytable(PlannerInfo *root,
 	fdw_private_list = NIL;
 	direct_modify_plans = NULL;
 	i = 0;
-	foreach(lc, resultRelations)
+	forboth(lc, resultRelations, lc2, subroots)
 	{
 		Index		rti = lfirst_int(lc);
+		PlannerInfo *subroot = lfirst_node(PlannerInfo, lc2);
 		FdwRoutine *fdwroutine;
 		List	   *fdw_private;
 		bool		direct_modify;
@@ -6641,16 +6645,16 @@ make_modifytable(PlannerInfo *root,
 		 * so it's not a baserel; and there are also corner cases for
 		 * updatable views where the target rel isn't a baserel.)
 		 */
-		if (rti < root->simple_rel_array_size &&
-			root->simple_rel_array[rti] != NULL)
+		if (rti < subroot->simple_rel_array_size &&
+			subroot->simple_rel_array[rti] != NULL)
 		{
-			RelOptInfo *resultRel = root->simple_rel_array[rti];
+			RelOptInfo *resultRel = subroot->simple_rel_array[rti];
 
 			fdwroutine = resultRel->fdwroutine;
 		}
 		else
 		{
-			RangeTblEntry *rte = planner_rt_fetch(rti, root);
+			RangeTblEntry *rte = planner_rt_fetch(rti, subroot);
 
 			Assert(rte->rtekind == RTE_RELATION);
 			if (rte->relkind == RELKIND_FOREIGN_TABLE)
@@ -6672,15 +6676,15 @@ make_modifytable(PlannerInfo *root,
 			fdwroutine->IterateDirectModify != NULL &&
 			fdwroutine->EndDirectModify != NULL &&
 			withCheckOptionLists == NIL &&
-			!has_row_triggers(root, rti, operation))
-			direct_modify = fdwroutine->PlanDirectModify(root, node, rti, i);
+			!has_row_triggers(subroot, rti, operation))
+			direct_modify = fdwroutine->PlanDirectModify(subroot, node, rti, i);
 		if (direct_modify)
 			direct_modify_plans = bms_add_member(direct_modify_plans, i);
 
 		if (!direct_modify &&
 			fdwroutine != NULL &&
 			fdwroutine->PlanForeignModify != NULL)
-			fdw_private = fdwroutine->PlanForeignModify(root, node, rti, i);
+			fdw_private = fdwroutine->PlanForeignModify(subroot, node, rti, i);
 		else
 			fdw_private = NIL;
 		fdw_private_list = lappend(fdw_private_list, fdw_private);