Remove unnecessary use of max_parallel_workers_per_gather

src/test/regress/expected/multi_distributed_transaction_id.out

@@ -142,6 +142,7 @@ INSERT INTO parallel_id_test VALUES (1234567), (1234567), (1234568), (1234568);
 ANALYSE parallel_id_test;
 SET LOCAL max_parallel_workers_per_gather TO 2;
 SET LOCAL parallel_tuple_cost TO 0;
+SET LOCAL parallel_setup_cost TO 0;
 EXPLAIN (COSTS OFF)
 SELECT a FROM parallel_id_test WHERE a = parallel_worker_transaction_id_test();
                          QUERY PLAN

src/test/regress/expected/multi_explain.out

@@ -1106,21 +1106,11 @@ EXPLAIN (COSTS FALSE, FORMAT YAML)
             Dependent Jobs:
               - Map Task Count: 2
                 Merge Task Count: 1
--- test parallel aggregates
-SET parallel_setup_cost=0;
-SET parallel_tuple_cost=0;
-SET min_parallel_relation_size=0;
-ERROR:  unrecognized configuration parameter "min_parallel_relation_size"
-SET min_parallel_table_scan_size=0;
-SET max_parallel_workers_per_gather=4;
 -- ensure local plans display correctly
 CREATE TABLE lineitem_clone (LIKE lineitem);
 EXPLAIN (COSTS FALSE) SELECT avg(l_linenumber) FROM lineitem_clone;
-Finalize Aggregate
-  ->  Gather
-        Workers Planned: 3
-        ->  Partial Aggregate
-              ->  Parallel Seq Scan on lineitem_clone
+Aggregate
+  ->  Seq Scan on lineitem_clone
 -- ensure distributed plans don't break
 EXPLAIN (COSTS FALSE) SELECT avg(l_linenumber) FROM lineitem;
 Aggregate

src/test/regress/expected/multi_partitioning.out

@@ -1605,13 +1605,6 @@ SELECT * FROM partitioning_hash_test JOIN partitioning_hash_join_test USING (id,
 (16 rows)
 
 -- set partition-wise join on and parallel to off
-SELECT success FROM run_command_on_workers('alter system set max_parallel_workers_per_gather = 0');
- success
----------------------------------------------------------------------
- t
- t
-(2 rows)
-
 SELECT success FROM run_command_on_workers('alter system set enable_partitionwise_join to on');
  success
 ---------------------------------------------------------------------
@@ -1716,13 +1709,6 @@ SELECT success FROM run_command_on_workers('alter system reset enable_indexonlys
  t
 (2 rows)
 
-SELECT success FROM run_command_on_workers('alter system reset max_parallel_workers_per_gather');
- success
----------------------------------------------------------------------
- t
- t
-(2 rows)
-
 SELECT success FROM run_command_on_workers('select pg_reload_conf()');
  success
 ---------------------------------------------------------------------

src/test/regress/sql/multi_distributed_transaction_id.sql

@@ -98,6 +98,7 @@ ANALYSE parallel_id_test;
 
 SET LOCAL max_parallel_workers_per_gather TO 2;
 SET LOCAL parallel_tuple_cost TO 0;
+SET LOCAL parallel_setup_cost TO 0;
 
 EXPLAIN (COSTS OFF)
 SELECT a FROM parallel_id_test WHERE a = parallel_worker_transaction_id_test();

src/test/regress/sql/multi_explain.sql

@@ -485,13 +485,6 @@ EXPLAIN (COSTS FALSE, FORMAT YAML)
 	AND o_custkey = c_custkey
 	AND l_suppkey = s_suppkey;
 
--- test parallel aggregates
-SET parallel_setup_cost=0;
-SET parallel_tuple_cost=0;
-SET min_parallel_relation_size=0;
-SET min_parallel_table_scan_size=0;
-SET max_parallel_workers_per_gather=4;
-
 -- ensure local plans display correctly
 CREATE TABLE lineitem_clone (LIKE lineitem);
 EXPLAIN (COSTS FALSE) SELECT avg(l_linenumber) FROM lineitem_clone;

src/test/regress/sql/multi_partitioning.sql

@@ -987,7 +987,6 @@ EXPLAIN (COSTS OFF)
 SELECT * FROM partitioning_hash_test JOIN partitioning_hash_join_test USING (id, subid);
 
 -- set partition-wise join on and parallel to off
-SELECT success FROM run_command_on_workers('alter system set max_parallel_workers_per_gather = 0');
 SELECT success FROM run_command_on_workers('alter system set enable_partitionwise_join to on');
 SELECT success FROM run_command_on_workers('select pg_reload_conf()');
 
@@ -1009,7 +1008,6 @@ SELECT success FROM run_command_on_workers('alter system reset enable_mergejoin'
 SELECT success FROM run_command_on_workers('alter system reset enable_nestloop');
 SELECT success FROM run_command_on_workers('alter system reset enable_indexscan');
 SELECT success FROM run_command_on_workers('alter system reset enable_indexonlyscan');
-SELECT success FROM run_command_on_workers('alter system reset max_parallel_workers_per_gather');
 SELECT success FROM run_command_on_workers('select pg_reload_conf()');
 
 RESET enable_partitionwise_join;