From: Pavan Deolasee <pavan.deolasee@gmail.com>
Date: Tue, 21 Aug 2018 09:54:13 +0000 (+0530)
Subject: Ensure that RemoteSubplan is marked parallel unsafe.
X-Git-Tag: XL_10_R1BETA1~28
X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=27c1751cbfdd06046cf38b37952d14691bc1295d;p=postgres-xl.git

Ensure that RemoteSubplan is marked parallel unsafe.

We can't support multiple backends running RemoteSubplan in parallel. So block
that. In fact, we'd already done so by setting parallel_safe to false while
creating the path, but there is another code path which builds the plan node
directly and we'd missed that.
---

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index e561448570..cae36be417 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -5890,6 +5890,9 @@ make_remotesubplan(PlannerInfo *root,
 	plan->righttree = NULL;
 	copy_plan_costsize(plan, lefttree);
 
+	/* RemoteSubplan is not parallel_safe */
+	plan->parallel_safe = false;
+
 	node->cursor = get_internal_cursor();
 	node->unique = 0;
 	return node;
diff --git a/src/test/regress/expected/select_parallel.out b/src/test/regress/expected/select_parallel.out
index 82069afc0f..e32bc9b8f1 100644
--- a/src/test/regress/expected/select_parallel.out
+++ b/src/test/regress/expected/select_parallel.out
@@ -134,20 +134,17 @@ alter table tenk2 set (parallel_workers = 0);
 explain (costs off)
 	select count(*) from tenk1 where (two, four) not in
 	(select hundred, thousand from tenk2 where thousand > 100);
-                                     QUERY PLAN                                      
--------------------------------------------------------------------------------------
- Finalize Aggregate
+                               QUERY PLAN                                
+-------------------------------------------------------------------------
+ Aggregate
    ->  Remote Subquery Scan on all (datanode_1,datanode_2)
-         ->  Gather
-               Workers Planned: 4
-               ->  Partial Aggregate
-                     ->  Parallel Seq Scan on tenk1
-                           Filter: (NOT (hashed SubPlan 1))
-                           SubPlan 1
-                             ->  Remote Subquery Scan on all (datanode_1,datanode_2)
-                                   ->  Seq Scan on tenk2
-                                         Filter: (thousand > 100)
-(11 rows)
+         ->  Seq Scan on tenk1
+               Filter: (NOT (hashed SubPlan 1))
+               SubPlan 1
+                 ->  Remote Subquery Scan on all (datanode_1,datanode_2)
+                       ->  Seq Scan on tenk2
+                             Filter: (thousand > 100)
+(8 rows)
 
 select count(*) from tenk1 where (two, four) not in
 	(select hundred, thousand from tenk2 where thousand > 100);