3 files changed, 138 insertions, 34 deletions

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index b3894d07607..029552b152b 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -3429,6 +3429,62 @@ select c2, sum from "S 1"."T 1" t1, lateral (select sum(t2.c1 + t1."C 1") sum fr
 (2 rows)
 
 reset enable_hashagg;
+-- bug #15613: bad plan for foreign table scan with lateral reference
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT ref_0.c2, subq_1.*
+FROM
+    "S 1"."T 1" AS ref_0,
+    LATERAL (
+        SELECT ref_0."C 1" c1, subq_0.*
+        FROM (SELECT ref_0.c2, ref_1.c3
+              FROM ft1 AS ref_1) AS subq_0
+             RIGHT JOIN ft2 AS ref_3 ON (subq_0.c3 = ref_3.c3)
+    ) AS subq_1
+WHERE ref_0."C 1" < 10 AND subq_1.c3 = '00001'
+ORDER BY ref_0."C 1";
+                                               QUERY PLAN                                                
+---------------------------------------------------------------------------------------------------------
+ Nested Loop
+   Output: ref_0.c2, ref_0."C 1", (ref_0.c2), ref_1.c3, ref_0."C 1"
+   ->  Nested Loop
+         Output: ref_0.c2, ref_0."C 1", ref_1.c3, (ref_0.c2)
+         ->  Index Scan using t1_pkey on "S 1"."T 1" ref_0
+               Output: ref_0."C 1", ref_0.c2, ref_0.c3, ref_0.c4, ref_0.c5, ref_0.c6, ref_0.c7, ref_0.c8
+               Index Cond: (ref_0."C 1" < 10)
+         ->  Foreign Scan on public.ft1 ref_1
+               Output: ref_1.c3, ref_0.c2
+               Remote SQL: SELECT c3 FROM "S 1"."T 1" WHERE ((c3 = '00001'::text))
+   ->  Materialize
+         Output: ref_3.c3
+         ->  Foreign Scan on public.ft2 ref_3
+               Output: ref_3.c3
+               Remote SQL: SELECT c3 FROM "S 1"."T 1" WHERE ((c3 = '00001'::text))
+(15 rows)
+
+SELECT ref_0.c2, subq_1.*
+FROM
+    "S 1"."T 1" AS ref_0,
+    LATERAL (
+        SELECT ref_0."C 1" c1, subq_0.*
+        FROM (SELECT ref_0.c2, ref_1.c3
+              FROM ft1 AS ref_1) AS subq_0
+             RIGHT JOIN ft2 AS ref_3 ON (subq_0.c3 = ref_3.c3)
+    ) AS subq_1
+WHERE ref_0."C 1" < 10 AND subq_1.c3 = '00001'
+ORDER BY ref_0."C 1";
+ c2 | c1 | c2 |  c3   
+----+----+----+-------
+  1 |  1 |  1 | 00001
+  2 |  2 |  2 | 00001
+  3 |  3 |  3 | 00001
+  4 |  4 |  4 | 00001
+  5 |  5 |  5 | 00001
+  6 |  6 |  6 | 00001
+  7 |  7 |  7 | 00001
+  8 |  8 |  8 | 00001
+  9 |  9 |  9 | 00001
+(9 rows)
+
 -- Check with placeHolderVars
 explain (verbose, costs off)
 select sum(q.a), count(q.b) from ft4 left join (select 13, avg(ft1.c1), sum(ft2.c1) from ft1 right join ft2 on (ft1.c1 = ft2.c1)) q(a, b, c) on (ft4.c1 <= q.b);
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 7fcac81e2e4..994cec50ce8 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -937,6 +937,9 @@ postgresGetForeignPaths(PlannerInfo *root,
 	 * baserestrict conditions we were able to send to remote, there might
 	 * actually be an indexscan happening there).  We already did all the work
 	 * to estimate cost and size of this path.
+	 *
+	 * Although this path uses no join clauses, it could still have required
+	 * parameterization due to LATERAL refs in its tlist.
 	 */
 	path = create_foreignscan_path(root, baserel,
 								   NULL,	/* default pathtarget */
@@ -944,7 +947,7 @@ postgresGetForeignPaths(PlannerInfo *root,
 								   fpinfo->startup_cost,
 								   fpinfo->total_cost,
 								   NIL, /* no pathkeys */
-								   NULL,	/* no outer rel either */
+								   baserel->lateral_relids,
 								   NULL,	/* no extra plan */
 								   NIL);	/* no fdw_private list */
 	add_path(baserel, (Path *) path);
@@ -3295,7 +3298,7 @@ execute_foreign_modify(EState *estate,
 					   TupleTableSlot *planSlot)
 {
 	PgFdwModifyState *fmstate = (PgFdwModifyState *) resultRelInfo->ri_FdwState;
-	ItemPointer	ctid = NULL;
+	ItemPointer ctid = NULL;
 	const char **p_values;
 	PGresult   *res;
 	int			n_rows;
@@ -3936,8 +3939,9 @@ apply_returning_filter(PgFdwDirectModifyState *dmstate,
 	ExecStoreVirtualTuple(resultSlot);
 
 	/*
-	 * If we have any system columns to return, materialize a heap tuple in the
-	 * slot from column values set above and install system columns in that tuple.
+	 * If we have any system columns to return, materialize a heap tuple in
+	 * the slot from column values set above and install system columns in
+	 * that tuple.
 	 */
 	if (dmstate->hasSystemCols)
 	{
@@ -4943,16 +4947,28 @@ add_paths_with_pathkeys_for_rel(PlannerInfo *root, RelOptInfo *rel,
 								 useful_pathkeys,
 								 -1.0);
 
-		add_path(rel, (Path *)
-				 create_foreignscan_path(root, rel,
-										 NULL,
-										 rows,
-										 startup_cost,
-										 total_cost,
-										 useful_pathkeys,
-										 NULL,
-										 sorted_epq_path,
-										 NIL));
+		if (IS_SIMPLE_REL(rel))
+			add_path(rel, (Path *)
+					 create_foreignscan_path(root, rel,
+											 NULL,
+											 rows,
+											 startup_cost,
+											 total_cost,
+											 useful_pathkeys,
+											 rel->lateral_relids,
+											 sorted_epq_path,
+											 NIL));
+		else
+			add_path(rel, (Path *)
+					 create_foreign_join_path(root, rel,
+											  NULL,
+											  rows,
+											  startup_cost,
+											  total_cost,
+											  useful_pathkeys,
+											  rel->lateral_relids,
+											  sorted_epq_path,
+											  NIL));
 	}
 }
 
@@ -5088,6 +5104,13 @@ postgresGetForeignJoinPaths(PlannerInfo *root,
 		return;
 
 	/*
+	 * This code does not work for joins with lateral references, since those
+	 * must have parameterized paths, which we don't generate yet.
+	 */
+	if (!bms_is_empty(joinrel->lateral_relids))
+		return;
+
+	/*
 	 * Create unfinished PgFdwRelationInfo entry which is used to indicate
 	 * that the join relation is already considered, so that we won't waste
 	 * time in judging safety of join pushdown and adding the same paths again
@@ -5171,16 +5194,16 @@ postgresGetForeignJoinPaths(PlannerInfo *root,
 	 * Create a new join path and add it to the joinrel which represents a
 	 * join between foreign tables.
 	 */
-	joinpath = create_foreignscan_path(root,
-									   joinrel,
-									   NULL,	/* default pathtarget */
-									   rows,
-									   startup_cost,
-									   total_cost,
-									   NIL, /* no pathkeys */
-									   NULL,	/* no required_outer */
-									   epq_path,
-									   NIL);	/* no fdw_private */
+	joinpath = create_foreign_join_path(root,
+										joinrel,
+										NULL,	/* default pathtarget */
+										rows,
+										startup_cost,
+										total_cost,
+										NIL,	/* no pathkeys */
+										joinrel->lateral_relids,
+										epq_path,
+										NIL);	/* no fdw_private */
 
 	/* Add generated path into joinrel by add_path(). */
 	add_path(joinrel, (Path *) joinpath);
@@ -5515,16 +5538,15 @@ add_foreign_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel,
 	fpinfo->total_cost = total_cost;
 
 	/* Create and add foreign path to the grouping relation. */
-	grouppath = create_foreignscan_path(root,
-										grouped_rel,
-										grouped_rel->reltarget,
-										rows,
-										startup_cost,
-										total_cost,
-										NIL,	/* no pathkeys */
-										NULL,	/* no required_outer */
-										NULL,
-										NIL);	/* no fdw_private */
+	grouppath = create_foreign_upper_path(root,
+										  grouped_rel,
+										  grouped_rel->reltarget,
+										  rows,
+										  startup_cost,
+										  total_cost,
+										  NIL,	/* no pathkeys */
+										  NULL,
+										  NIL); /* no fdw_private */
 
 	/* Add generated path into grouped_rel by add_path(). */
 	add_path(grouped_rel, (Path *) grouppath);
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index f438165650c..bab8479cf6a 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -879,6 +879,32 @@ select c2, sum from "S 1"."T 1" t1, lateral (select sum(t2.c1 + t1."C 1") sum fr
 select c2, sum from "S 1"."T 1" t1, lateral (select sum(t2.c1 + t1."C 1") sum from ft2 t2 group by t2.c1) qry where t1.c2 * 2 = qry.sum and t1.c2 < 3 and t1."C 1" < 100 order by 1;
 reset enable_hashagg;
 
+-- bug #15613: bad plan for foreign table scan with lateral reference
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT ref_0.c2, subq_1.*
+FROM
+    "S 1"."T 1" AS ref_0,
+    LATERAL (
+        SELECT ref_0."C 1" c1, subq_0.*
+        FROM (SELECT ref_0.c2, ref_1.c3
+              FROM ft1 AS ref_1) AS subq_0
+             RIGHT JOIN ft2 AS ref_3 ON (subq_0.c3 = ref_3.c3)
+    ) AS subq_1
+WHERE ref_0."C 1" < 10 AND subq_1.c3 = '00001'
+ORDER BY ref_0."C 1";
+
+SELECT ref_0.c2, subq_1.*
+FROM
+    "S 1"."T 1" AS ref_0,
+    LATERAL (
+        SELECT ref_0."C 1" c1, subq_0.*
+        FROM (SELECT ref_0.c2, ref_1.c3
+              FROM ft1 AS ref_1) AS subq_0
+             RIGHT JOIN ft2 AS ref_3 ON (subq_0.c3 = ref_3.c3)
+    ) AS subq_1
+WHERE ref_0."C 1" < 10 AND subq_1.c3 = '00001'
+ORDER BY ref_0."C 1";
+
 -- Check with placeHolderVars
 explain (verbose, costs off)
 select sum(q.a), count(q.b) from ft4 left join (select 13, avg(ft1.c1), sum(ft2.c1) from ft1 right join ft2 on (ft1.c1 = ft2.c1)) q(a, b, c) on (ft4.c1 <= q.b);