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tenderwgyjhjstz
tenderwg
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yjhjstz
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Fix "unexpected gang size" issue.
In postgres planner, after top_plan having been produced, we have to adjust the Motion type of subplans, which call cdbllize_decorate_subplans_with_motions(). If subquery has another subquery, for example, in this test case, the second subquery's motion type is set to Gather but should be Broadcast. The root cause is that we forget to change local subFlow when its subplan has changed.
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‎src/backend/cdb/cdbllize.c‎

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@@ -1025,6 +1025,7 @@ fix_subplan_motion(PlannerInfo *root, Plan *subplan, Flow *outer_query_flow)
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{
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initPlans = list_concat(initPlans, subplan->initPlan);
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subplan = subplan->lefttree;
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subFlow = subplan->flow;
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}
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/*
@@ -1041,6 +1042,7 @@ fix_subplan_motion(PlannerInfo *root, Plan *subplan, Flow *outer_query_flow)
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sendSlice = strippedMotion->senderSliceInfo;
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subplan = subplan->lefttree;
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subFlow = subplan->flow;
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initPlans = list_concat(initPlans, strippedMotion->plan.initPlan);
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}
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else

‎src/test/regress/expected/subselect_gp.out‎

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@@ -298,6 +298,51 @@ select * from mrs_u1 join mrs_u2 on mrs_u1.a=mrs_u2.a where mrs_u1.a in (1,11) o
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drop table if exists mrs_u1;
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drop table if exists mrs_u2;
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--
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-- Set right motion type to subquery
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--
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drop table if exists gs_tab;
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NOTICE: table "gs_tab" does not exist, skipping
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create table gs_tab(a int, b int, c int) distributed by (a);
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insert into gs_tab values (1,1,1),(2,2,2);
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explain(costs off)
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select a from gs_tab t1 where b in
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(select b from gs_tab t2 where c in
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(select c from gs_tab t3)
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or (c >= 2))
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or (b <= 3)
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order by a;
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QUERY PLAN
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-------------------------------------------------------------------------------
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Gather Motion 3:1 (slice1; segments: 3)
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Merge Key: t1.a
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-> Sort
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Sort Key: t1.a
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-> Seq Scan on gs_tab t1
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Filter: ((hashed SubPlan 2) OR (b <= 3))
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SubPlan 2
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-> Broadcast Motion 3:3 (slice2; segments: 3)
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-> Seq Scan on gs_tab t2
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Filter: ((hashed SubPlan 1) OR (c >= 2))
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SubPlan 1
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-> Broadcast Motion 3:3 (slice3; segments: 3)
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-> Seq Scan on gs_tab t3
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Optimizer: Postgres query optimizer
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(14 rows)
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select a from gs_tab t1 where b in
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(select b from gs_tab t2 where c in
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(select c from gs_tab t3)
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or (c >= 2))
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or (b <= 3)
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order by a;
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a
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---
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1
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2
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(2 rows)
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drop table if exists gs_tab;
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--
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-- MPP-13758
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--
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drop table if exists csq_m1;

‎src/test/regress/expected/subselect_gp_optimizer.out‎

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@@ -275,6 +275,67 @@ select * from mrs_u1 join mrs_u2 on mrs_u1.a=mrs_u2.a where mrs_u1.a in (1,11) o
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drop table if exists mrs_u1;
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drop table if exists mrs_u2;
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--
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-- Set right motion type to subquery
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--
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drop table if exists gs_tab;
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NOTICE: table "gs_tab" does not exist, skipping
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create table gs_tab(a int, b int, c int) distributed by (a);
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insert into gs_tab values (1,1,1),(2,2,2);
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explain(costs off)
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select a from gs_tab t1 where b in
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(select b from gs_tab t2 where c in
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(select c from gs_tab t3)
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or (c >= 2))
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or (b <= 3)
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order by a;
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QUERY PLAN
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--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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Gather Motion 3:1 (slice1; segments: 3)
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Merge Key: gs_tab_2.a
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-> Sort
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Sort Key: gs_tab_2.a
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-> Result
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Filter: (CASE WHEN ((count((true))) > '0'::bigint) THEN CASE WHEN ((sum((CASE WHEN ((gs_tab_2.b = gs_tab_1.b) IS NULL) THEN 1 ELSE 0 END))) = (count((true)))) THEN NULL::boolean ELSE true END ELSE false END OR (gs_tab_2.b <= 3))
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-> GroupAggregate
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Group Key: gs_tab_2.a, gs_tab_2.b, gs_tab_2.ctid, gs_tab_2.gp_segment_id
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-> Sort
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Sort Key: gs_tab_2.a, gs_tab_2.b, gs_tab_2.ctid, gs_tab_2.gp_segment_id
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-> Nested Loop Left Join
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Join Filter: ((gs_tab_2.b = gs_tab_1.b) IS NOT FALSE)
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-> Seq Scan on gs_tab gs_tab_2
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-> Materialize
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-> Result
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-> Broadcast Motion 3:3 (slice2; segments: 3)
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-> Result
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Filter: (CASE WHEN ((count((true))) > '0'::bigint) THEN CASE WHEN ((sum((CASE WHEN ((gs_tab_1.c = gs_tab.c) IS NULL) THEN 1 ELSE 0 END))) = (count((true)))) THEN NULL::boolean ELSE true END ELSE false END OR (gs_tab_1.c >= 2))
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-> GroupAggregate
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Group Key: gs_tab_1.a, gs_tab_1.b, gs_tab_1.c, gs_tab_1.ctid, gs_tab_1.gp_segment_id
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-> Sort
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Sort Key: gs_tab_1.a, gs_tab_1.b, gs_tab_1.c, gs_tab_1.ctid, gs_tab_1.gp_segment_id
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-> Nested Loop Left Join
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Join Filter: ((gs_tab_1.c = gs_tab.c) IS NOT FALSE)
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-> Seq Scan on gs_tab gs_tab_1
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-> Materialize
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-> Result
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-> Broadcast Motion 3:3 (slice3; segments: 3)
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-> Seq Scan on gs_tab
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Optimizer: Pivotal Optimizer (GPORCA)
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(30 rows)
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select a from gs_tab t1 where b in
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(select b from gs_tab t2 where c in
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(select c from gs_tab t3)
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or (c >= 2))
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or (b <= 3)
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order by a;
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a
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---
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1
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2
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(2 rows)
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drop table if exists gs_tab;
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--
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-- MPP-13758
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--
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drop table if exists csq_m1;

‎src/test/regress/sql/subselect_gp.sql‎

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@@ -135,6 +135,31 @@ select * from mrs_u1 join mrs_u2 on mrs_u1.a=mrs_u2.a where mrs_u1.a in (1,11) o
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drop table if exists mrs_u1;
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drop table if exists mrs_u2;
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--
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-- Set right motion type to subquery
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--
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drop table if exists gs_tab;
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create table gs_tab(a int, b int, c int) distributed by (a);
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insert into gs_tab values (1,1,1),(2,2,2);
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explain(costs off)
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select a from gs_tab t1 where b in
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(select b from gs_tab t2 where c in
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(select c from gs_tab t3)
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or (c >= 2))
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or (b <= 3)
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order by a;
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select a from gs_tab t1 where b in
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(select b from gs_tab t2 where c in
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(select c from gs_tab t3)
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or (c >= 2))
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or (b <= 3)
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order by a;
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drop table if exists gs_tab;
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--
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-- MPP-13758
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--

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