3 files changed, 67 insertions, 10 deletions

diff --git a/src/backend/executor/nodeLimit.c b/src/backend/executor/nodeLimit.c
index baa669abe84..5e4d02ce4a6 100644
--- a/src/backend/executor/nodeLimit.c
+++ b/src/backend/executor/nodeLimit.c
@@ -129,19 +129,17 @@ ExecLimit(PlanState *pstate)
 				 * we are at the end of the window, return NULL without
 				 * advancing the subplan or the position variable; but change
 				 * the state machine state to record having done so.
+				 *
+				 * Once at the end, ideally, we can shut down parallel
+				 * resources but that would destroy the parallel context which
+				 * would be required for rescans.  To do that, we need to find
+				 * a way to pass down more information about whether rescans
+				 * are possible.
 				 */
 				if (!node->noCount &&
 					node->position - node->offset >= node->count)
 				{
 					node->lstate = LIMIT_WINDOWEND;
-
-					/*
-					 * If we know we won't need to back up, we can release
-					 * resources at this point.
-					 */
-					if (!(node->ps.state->es_top_eflags & EXEC_FLAG_BACKWARD))
-						(void) ExecShutdownNode(outerPlan);
-
 					return NULL;
 				}
 
diff --git a/src/test/regress/expected/select_parallel.out b/src/test/regress/expected/select_parallel.out
index 0eca76cb41e..191ffe7e238 100644
--- a/src/test/regress/expected/select_parallel.out
+++ b/src/test/regress/expected/select_parallel.out
@@ -455,9 +455,48 @@ select * from
   9000 | 3
 (3 rows)
 
-reset enable_material;
+-- test rescans for a Limit node with a parallel node beneath it.
 reset enable_seqscan;
+set enable_indexonlyscan to off;
+set enable_indexscan to off;
+alter table tenk1 set (parallel_workers = 0);
+alter table tenk2 set (parallel_workers = 1);
+explain (costs off)
+select count(*) from tenk1
+  left join (select tenk2.unique1 from tenk2 order by 1 limit 1000) ss
+  on tenk1.unique1 < ss.unique1 + 1
+  where tenk1.unique1 < 2;
+                         QUERY PLAN                         
+------------------------------------------------------------
+ Aggregate
+   ->  Nested Loop Left Join
+         Join Filter: (tenk1.unique1 < (tenk2.unique1 + 1))
+         ->  Seq Scan on tenk1
+               Filter: (unique1 < 2)
+         ->  Limit
+               ->  Gather Merge
+                     Workers Planned: 1
+                     ->  Sort
+                           Sort Key: tenk2.unique1
+                           ->  Parallel Seq Scan on tenk2
+(11 rows)
+
+select count(*) from tenk1
+  left join (select tenk2.unique1 from tenk2 order by 1 limit 1000) ss
+  on tenk1.unique1 < ss.unique1 + 1
+  where tenk1.unique1 < 2;
+ count 
+-------
+  1999
+(1 row)
+
+--reset the value of workers for each table as it was before this test.
+alter table tenk1 set (parallel_workers = 4);
+alter table tenk2 reset (parallel_workers);
+reset enable_material;
 reset enable_bitmapscan;
+reset enable_indexonlyscan;
+reset enable_indexscan;
 -- test parallel bitmap heap scan.
 set enable_seqscan to off;
 set enable_indexscan to off;
diff --git a/src/test/regress/sql/select_parallel.sql b/src/test/regress/sql/select_parallel.sql
index 03c056b8b77..11e77355332 100644
--- a/src/test/regress/sql/select_parallel.sql
+++ b/src/test/regress/sql/select_parallel.sql
@@ -168,9 +168,29 @@ select * from
   (select count(*) from tenk1 where thousand > 99) ss
   right join (values (1),(2),(3)) v(x) on true;
 
-reset enable_material;
+-- test rescans for a Limit node with a parallel node beneath it.
 reset enable_seqscan;
+set enable_indexonlyscan to off;
+set enable_indexscan to off;
+alter table tenk1 set (parallel_workers = 0);
+alter table tenk2 set (parallel_workers = 1);
+explain (costs off)
+select count(*) from tenk1
+  left join (select tenk2.unique1 from tenk2 order by 1 limit 1000) ss
+  on tenk1.unique1 < ss.unique1 + 1
+  where tenk1.unique1 < 2;
+select count(*) from tenk1
+  left join (select tenk2.unique1 from tenk2 order by 1 limit 1000) ss
+  on tenk1.unique1 < ss.unique1 + 1
+  where tenk1.unique1 < 2;
+--reset the value of workers for each table as it was before this test.
+alter table tenk1 set (parallel_workers = 4);
+alter table tenk2 reset (parallel_workers);
+
+reset enable_material;
 reset enable_bitmapscan;
+reset enable_indexonlyscan;
+reset enable_indexscan;
 
 -- test parallel bitmap heap scan.
 set enable_seqscan to off;