0002-Test-rescans-when-parallel-node-is-beneath-Limit-nod.patch

From 294b2715aee208f1eb70a4bfa28ca8afab6d6829 Mon Sep 17 00:00:00 2001
From: Amit Kapila <akapila@postgresql.org>
Date: Mon, 2 Sep 2019 13:04:26 +0530
Subject: [PATCH 2/2] Test rescans when parallel node is beneath Limit node.

---
 src/test/regress/expected/select_parallel.out | 34 ++++++++++++++++++++++++++-
 src/test/regress/sql/select_parallel.sql      | 17 +++++++++++++-
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/src/test/regress/expected/select_parallel.out b/src/test/regress/expected/select_parallel.out
index 04aecef..b8d7f67 100644
--- a/src/test/regress/expected/select_parallel.out
+++ b/src/test/regress/expected/select_parallel.out
@@ -469,9 +469,41 @@ 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;
+alter table tenk2 set (parallel_workers = 1);
+explain (costs off)
+select count(*) from tenk1
+  left join (select tenk2.unique1 from tenk2 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))
+         ->  Index Scan using tenk1_unique1 on tenk1
+               Index Cond: (unique1 < 2)
+         ->  Limit
+               ->  Gather
+                     Workers Planned: 1
+                     ->  Parallel Seq Scan on tenk2
+(9 rows)
+
+select count(*) from tenk1
+  left join (select tenk2.unique1 from tenk2 limit 1000) ss
+  on tenk1.unique1 < ss.unique1 + 1
+  where tenk1.unique1 < 2;
+ count 
+-------
+  2000
+(1 row)
+
+alter table tenk2 reset (parallel_workers);
+reset enable_material;
 reset enable_bitmapscan;
+reset enable_indexonlyscan;
 -- 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 2c05661..6965c69 100644
--- a/src/test/regress/sql/select_parallel.sql
+++ b/src/test/regress/sql/select_parallel.sql
@@ -173,9 +173,24 @@ 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;
+alter table tenk2 set (parallel_workers = 1);
+explain (costs off)
+select count(*) from tenk1
+  left join (select tenk2.unique1 from tenk2 limit 1000) ss
+  on tenk1.unique1 < ss.unique1 + 1
+  where tenk1.unique1 < 2;
+select count(*) from tenk1
+  left join (select tenk2.unique1 from tenk2 limit 1000) ss
+  on tenk1.unique1 < ss.unique1 + 1
+  where tenk1.unique1 < 2;
+alter table tenk2 reset (parallel_workers);
+
+reset enable_material;
 reset enable_bitmapscan;
+reset enable_indexonlyscan;
 
 -- test parallel bitmap heap scan.
 set enable_seqscan to off;
-- 
1.8.3.1