test_with_noleader.patch

diff --git a/src/test/regress/expected/select_parallel.out b/src/test/regress/expected/select_parallel.out
index ff00d47..ff3e083 100644
--- a/src/test/regress/expected/select_parallel.out
+++ b/src/test/regress/expected/select_parallel.out
@@ -35,6 +35,40 @@ select round(avg(aa)), sum(aa) from a_star a1;
     14 | 355
 (1 row)
 
+-- leader participation disabled.
+set parallel_leader_participation = off;
+-- Note : With no leader, subplans become non-partial, unless parallel_workers
+-- is set for each of them.
+alter table c_star set (parallel_workers = 3);
+alter table d_star set (parallel_workers = 3);
+alter table a_star set (parallel_workers = 3);
+alter table b_star set (parallel_workers = 3);
+alter table e_star set (parallel_workers = 3);
+alter table f_star set (parallel_workers = 3);
+explain (costs off)
+  select round(avg(aa)), sum(aa) from a_star;
+                     QUERY PLAN                      
+-----------------------------------------------------
+ Finalize Aggregate
+   ->  Gather
+         Workers Planned: 3
+         ->  Partial Aggregate
+               ->  Parallel Append
+                     ->  Parallel Seq Scan on a_star
+                     ->  Parallel Seq Scan on b_star
+                     ->  Parallel Seq Scan on c_star
+                     ->  Parallel Seq Scan on d_star
+                     ->  Parallel Seq Scan on e_star
+                     ->  Parallel Seq Scan on f_star
+(11 rows)
+
+select round(avg(aa)), sum(aa) from a_star a1_1;
+ round | sum 
+-------+-----
+    14 | 355
+(1 row)
+
+reset parallel_leader_participation;
 -- Parallel Append with both partial and non-partial subplans
 alter table c_star set (parallel_workers = 0);
 alter table d_star set (parallel_workers = 0);
@@ -61,6 +95,32 @@ select round(avg(aa)), sum(aa) from a_star a2;
     14 | 355
 (1 row)
 
+-- leader participation disabled.
+set parallel_leader_participation = off;
+explain (costs off)
+  select round(avg(aa)), sum(aa) from a_star;
+                     QUERY PLAN                      
+-----------------------------------------------------
+ Finalize Aggregate
+   ->  Gather
+         Workers Planned: 3
+         ->  Partial Aggregate
+               ->  Parallel Append
+                     ->  Seq Scan on d_star
+                     ->  Seq Scan on c_star
+                     ->  Parallel Seq Scan on a_star
+                     ->  Parallel Seq Scan on b_star
+                     ->  Parallel Seq Scan on e_star
+                     ->  Parallel Seq Scan on f_star
+(11 rows)
+
+select round(avg(aa)), sum(aa) from a_star a2_1;
+ round | sum 
+-------+-----
+    14 | 355
+(1 row)
+
+reset parallel_leader_participation;
 -- Parallel Append with only non-partial subplans
 alter table a_star set (parallel_workers = 0);
 alter table b_star set (parallel_workers = 0);
@@ -89,6 +149,32 @@ select round(avg(aa)), sum(aa) from a_star a3;
     14 | 355
 (1 row)
 
+-- leader participation disabled.
+set parallel_leader_participation = off;
+explain (costs off)
+  select round(avg(aa)), sum(aa) from a_star;
+                 QUERY PLAN                 
+--------------------------------------------
+ Finalize Aggregate
+   ->  Gather
+         Workers Planned: 3
+         ->  Partial Aggregate
+               ->  Parallel Append
+                     ->  Seq Scan on d_star
+                     ->  Seq Scan on f_star
+                     ->  Seq Scan on e_star
+                     ->  Seq Scan on b_star
+                     ->  Seq Scan on c_star
+                     ->  Seq Scan on a_star
+(11 rows)
+
+select round(avg(aa)), sum(aa) from a_star a3_1;
+ round | sum 
+-------+-----
+    14 | 355
+(1 row)
+
+reset parallel_leader_participation;
 -- Disable Parallel Append
 alter table a_star reset (parallel_workers);
 alter table b_star reset (parallel_workers);
@@ -120,6 +206,29 @@ select round(avg(aa)), sum(aa) from a_star a4;
     14 | 355
 (1 row)
 
+-- leader participation disabled.
+set parallel_leader_participation = off;
+explain (costs off)
+  select round(avg(aa)), sum(aa) from a_star;
+           QUERY PLAN           
+--------------------------------
+ Aggregate
+   ->  Append
+         ->  Seq Scan on a_star
+         ->  Seq Scan on b_star
+         ->  Seq Scan on c_star
+         ->  Seq Scan on d_star
+         ->  Seq Scan on e_star
+         ->  Seq Scan on f_star
+(8 rows)
+
+select round(avg(aa)), sum(aa) from a_star a4_1;
+ round | sum 
+-------+-----
+    14 | 355
+(1 row)
+
+reset parallel_leader_participation;
 reset enable_parallel_append;
 -- test with leader participation disabled
 set parallel_leader_participation = off;
diff --git a/src/test/regress/sql/select_parallel.sql b/src/test/regress/sql/select_parallel.sql
index 1035d04..a79422f 100644
--- a/src/test/regress/sql/select_parallel.sql
+++ b/src/test/regress/sql/select_parallel.sql
@@ -19,6 +19,20 @@ set max_parallel_workers_per_gather=4;
 explain (costs off)
   select round(avg(aa)), sum(aa) from a_star;
 select round(avg(aa)), sum(aa) from a_star a1;
+-- leader participation disabled.
+set parallel_leader_participation = off;
+-- Note : With no leader, subplans become non-partial, unless parallel_workers
+-- is set for each of them.
+alter table c_star set (parallel_workers = 3);
+alter table d_star set (parallel_workers = 3);
+alter table a_star set (parallel_workers = 3);
+alter table b_star set (parallel_workers = 3);
+alter table e_star set (parallel_workers = 3);
+alter table f_star set (parallel_workers = 3);
+explain (costs off)
+  select round(avg(aa)), sum(aa) from a_star;
+select round(avg(aa)), sum(aa) from a_star a1_1;
+reset parallel_leader_participation;
 
 -- Parallel Append with both partial and non-partial subplans
 alter table c_star set (parallel_workers = 0);
@@ -26,6 +40,13 @@ alter table d_star set (parallel_workers = 0);
 explain (costs off)
   select round(avg(aa)), sum(aa) from a_star;
 select round(avg(aa)), sum(aa) from a_star a2;
+-- leader participation disabled.
+set parallel_leader_participation = off;
+explain (costs off)
+  select round(avg(aa)), sum(aa) from a_star;
+select round(avg(aa)), sum(aa) from a_star a2_1;
+reset parallel_leader_participation;
+
 
 -- Parallel Append with only non-partial subplans
 alter table a_star set (parallel_workers = 0);
@@ -35,6 +56,12 @@ alter table f_star set (parallel_workers = 0);
 explain (costs off)
   select round(avg(aa)), sum(aa) from a_star;
 select round(avg(aa)), sum(aa) from a_star a3;
+-- leader participation disabled.
+set parallel_leader_participation = off;
+explain (costs off)
+  select round(avg(aa)), sum(aa) from a_star;
+select round(avg(aa)), sum(aa) from a_star a3_1;
+reset parallel_leader_participation;
 
 -- Disable Parallel Append
 alter table a_star reset (parallel_workers);
@@ -47,6 +74,12 @@ set enable_parallel_append to off;
 explain (costs off)
   select round(avg(aa)), sum(aa) from a_star;
 select round(avg(aa)), sum(aa) from a_star a4;
+-- leader participation disabled.
+set parallel_leader_participation = off;
+explain (costs off)
+  select round(avg(aa)), sum(aa) from a_star;
+select round(avg(aa)), sum(aa) from a_star a4_1;
+reset parallel_leader_participation;
 reset enable_parallel_append;
 
 -- test with leader participation disabled