diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index 2396bd442fa4f61048fa35e129cfd8856a62a7f7..eb255bd12fd29096b7ba06a04f882ee12bad309b 100644
--- a/contrib/file_fdw/file_fdw.c
+++ b/contrib/file_fdw/file_fdw.c
@@ -541,6 +541,10 @@ fileGetForeignPaths(PlannerInfo *root,
* Create a ForeignPath node and add it as only possible path. We use the
* fdw_private list of the path to carry the convert_selectively option;
* it will be propagated into the fdw_private list of the Plan node.
+ *
+ * We don't support pushing join clauses into the quals of this path, but
+ * it could still have required parameterization due to LATERAL refs in
+ * its tlist.
*/
add_path(baserel, (Path *)
create_foreignscan_path(root, baserel,
@@ -549,7 +553,7 @@ fileGetForeignPaths(PlannerInfo *root,
startup_cost,
total_cost,
NIL, /* no pathkeys */
- NULL, /* no outer rel either */
+ baserel->lateral_relids,
NULL, /* no extra plan */
coptions));
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f6bb2fc472cdf5dbfc6c492bae1c5a1a0bb20614..c82eb6ed19769016369cb02f10199bdd7ea54e93 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -3420,6 +3420,62 @@ 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 f1552b2954122badc2a035a3b46d1bfd6ad48043..7ff514723c7bda4f9db9b7518537d0b5f8a68cff 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -897,6 +897,9 @@ 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 */
@@ -904,7 +907,7 @@ 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);
@@ -4374,7 +4377,7 @@ add_paths_with_pathkeys_for_rel(PlannerInfo *root, RelOptInfo *rel,
startup_cost,
total_cost,
useful_pathkeys,
- NULL,
+ rel->lateral_relids,
sorted_epq_path,
NIL));
}
@@ -4511,6 +4514,13 @@ postgresGetForeignJoinPaths(PlannerInfo *root,
if (joinrel->fdw_private)
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
@@ -4602,7 +4612,7 @@ postgresGetForeignJoinPaths(PlannerInfo *root,
startup_cost,
total_cost,
NIL, /* no pathkeys */
- NULL, /* no required_outer */
+ joinrel->lateral_relids,
epq_path,
NIL); /* no fdw_private */
@@ -4921,7 +4931,7 @@ add_foreign_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel,
startup_cost,
total_cost,
NIL, /* no pathkeys */
- NULL, /* no required_outer */
+ grouped_rel->lateral_relids,
NULL,
NIL); /* no fdw_private */
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index d3e7c71a2ff40fbaaaf1ca0a92d07c2d5f27caf2..d30afcbfb9f3ed9fc92257ec522e131270ccbd48 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -878,6 +878,32 @@ 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);
diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index b34c5f869005804df1c209bdfb41bf2960b6eb00..69a24112c0a671366927defb5e972385166679de 100644
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -1967,6 +1967,27 @@ create_foreignscan_path(PlannerInfo *root, RelOptInfo *rel,
{
ForeignPath *pathnode = makeNode(ForeignPath);
+ /*
+ * Since the path's required_outer should always include all the rel's
+ * lateral_relids, forcibly add those if necessary. This is a bit of a
+ * hack, but up till early 2019 the contrib FDWs failed to ensure that,
+ * and it's likely that the same error has propagated into many external
+ * FDWs. Don't risk modifying the passed-in relid set here.
+ */
+ if (rel->lateral_relids && !bms_is_subset(rel->lateral_relids,
+ required_outer))
+ required_outer = bms_union(required_outer, rel->lateral_relids);
+
+ /*
+ * Although this function is only designed to be used for scans of
+ * baserels, before v12 postgres_fdw abused it to make paths for join and
+ * upper rels. It will work for such cases as long as required_outer is
+ * empty (otherwise get_baserel_parampathinfo does the wrong thing), which
+ * fortunately is the expected case for now.
+ */
+ if (!bms_is_empty(required_outer) && !IS_SIMPLE_REL(rel))
+ elog(ERROR, "parameterized foreign joins are not supported yet");
+
pathnode->path.pathtype = T_ForeignScan;
pathnode->path.parent = rel;
pathnode->path.pathtarget = target ? target : rel->reltarget;
diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index 7125082812aa576d41a7f72925f02f61824c52fd..c890bd79325aaf4928772eaefc0bc9bf0d5d5488 100644
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -1041,6 +1041,9 @@ get_baserel_parampathinfo(PlannerInfo *root, RelOptInfo *baserel,
double rows;
ListCell *lc;
+ /* If rel has LATERAL refs, every path for it should account for them */
+ Assert(bms_is_subset(baserel->lateral_relids, required_outer));
+
/* Unparameterized paths have no ParamPathInfo */
if (bms_is_empty(required_outer))
return NULL;
@@ -1140,6 +1143,9 @@ get_joinrel_parampathinfo(PlannerInfo *root, RelOptInfo *joinrel,
double rows;
ListCell *lc;
+ /* If rel has LATERAL refs, every path for it should account for them */
+ Assert(bms_is_subset(joinrel->lateral_relids, required_outer));
+
/* Unparameterized paths have no ParamPathInfo or extra join clauses */
if (bms_is_empty(required_outer))
return NULL;
@@ -1336,6 +1342,9 @@ get_appendrel_parampathinfo(RelOptInfo *appendrel, Relids required_outer)
ParamPathInfo *ppi;
ListCell *lc;
+ /* If rel has LATERAL refs, every path for it should account for them */
+ Assert(bms_is_subset(appendrel->lateral_relids, required_outer));
+
/* Unparameterized paths have no ParamPathInfo */
if (bms_is_empty(required_outer))
return NULL;