3 files changed, 51 insertions, 0 deletions
diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index 972e3b0810a..e74aa094c02 100644
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -1809,6 +1809,28 @@ reparameterize_path(PlannerInfo *root, Path *path,
 		case T_SubqueryScan:
 			return create_subqueryscan_path(root, rel, path->pathkeys,
 											required_outer);
+		case T_Append:
+			{
+				AppendPath *apath = (AppendPath *) path;
+				List	   *childpaths = NIL;
+				ListCell   *lc;
+
+				/* Reparameterize the children */
+				foreach(lc, apath->subpaths)
+				{
+					Path	   *spath = (Path *) lfirst(lc);
+
+					spath = reparameterize_path(root, spath,
+												required_outer,
+												loop_count);
+					if (spath == NULL)
+						return NULL;
+					childpaths = lappend(childpaths, spath);
+				}
+				return (Path *)
+					create_append_path(rel, childpaths,
+									   required_outer);
+			}
 		default:
 			break;
 	}
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index d71da0b8137..be6e5468648 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -5153,6 +5153,25 @@ select * from
          Output: 3
 (11 rows)
 
+-- check handling of nested appendrels inside LATERAL
+select * from
+  ((select 2 as v) union all (select 3 as v)) as q1
+  cross join lateral
+  ((select * from
+      ((select 4 as v) union all (select 5 as v)) as q3)
+   union all
+   (select q1.v)
+  ) as q2;
+ v | v 
+---+---
+ 2 | 4
+ 2 | 5
+ 2 | 2
+ 3 | 4
+ 3 | 5
+ 3 | 3
+(6 rows)
+
 -- check we don't try to do a unique-ified semijoin with LATERAL
 explain (verbose, costs off)
 select * from
diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql
index fd05f5c8a32..b29aecba38d 100644
--- a/src/test/regress/sql/join.sql
+++ b/src/test/regress/sql/join.sql
@@ -1664,6 +1664,16 @@ select * from
     select * from (select 3 as z offset 0) z where z.z = x.x
   ) zz on zz.z = y.y;
 
+-- check handling of nested appendrels inside LATERAL
+select * from
+  ((select 2 as v) union all (select 3 as v)) as q1
+  cross join lateral
+  ((select * from
+      ((select 4 as v) union all (select 5 as v)) as q3)
+   union all
+   (select q1.v)
+  ) as q2;
+
 -- check we don't try to do a unique-ified semijoin with LATERAL
 explain (verbose, costs off)
 select * from