Force parallelism in partition_aggregate

Commit db0d67db2 tweaked sort costing, which however resulted in a
couple plan changes in our regression tests. Most of the new plans were
fine, but partition_aggregate were meant to test parallel plans and the
new plans were serial.

Fix that by lowering parallel_setup_cost to 0, which is enough to switch
to the parallel plan again.

Commit 1349d2790 already made the plans parallel again, but do this
anyway to keep the tests in sync with 15, to make backpatching simpler.

Report and patch by David Rowley.

Author: David Rowley
Reviewed-by: Tomas Vondra
Discussion: https://postgr.es/m/CAApHDvpVFgWzXdtUQkjyOPhNrNvumRi_=ftgS79KeAZ92tnHKQ@mail.gmail.com

diff --git a/src/test/regress/expected/partition_aggregate.out b/src/test/regress/expected/partition_aggregate.out
index 4b41ccf1aa81ada97e2a58c4c0998db39bac413b..db36e3a150af7d408dcce02fd2402028dad676ac 100644 (file)
--- a/src/test/regress/expected/partition_aggregate.out
+++ b/src/test/regress/expected/partition_aggregate.out
@@ -942,6 +942,7 @@ INSERT INTO pagg_tab_ml SELECT i % 30, i % 10, to_char(i % 4, 'FM0000') FROM gen
 ANALYZE pagg_tab_ml;
 -- For Parallel Append
 SET max_parallel_workers_per_gather TO 2;
+SET parallel_setup_cost = 0;
 -- Full aggregation at level 1 as GROUP BY clause matches with PARTITION KEY
 -- for level 1 only. For subpartitions, GROUP BY clause does not match with
 -- PARTITION KEY, but still we do not see a partial aggregation as array_agg()
@@ -1025,6 +1026,7 @@ SELECT a, sum(b), array_agg(distinct c), count(*) FROM pagg_tab_ml GROUP BY a HA
                            ->  Seq Scan on pagg_tab_ml_p2_s2 pagg_tab_ml_3
 (25 rows)
 
+RESET parallel_setup_cost;
 -- Full aggregation at level 1 as GROUP BY clause matches with PARTITION KEY
 -- for level 1 only. For subpartitions, GROUP BY clause does not match with
 -- PARTITION KEY, thus we will have a partial aggregation for them.

diff --git a/src/test/regress/sql/partition_aggregate.sql b/src/test/regress/sql/partition_aggregate.sql
index c17294b15b01f0130f30b04d217675d64f0c3b84..ab070fee24496d2dbe07b98b68e08bcbb6a3d0fd 100644 (file)
--- a/src/test/regress/sql/partition_aggregate.sql
+++ b/src/test/regress/sql/partition_aggregate.sql
@@ -222,6 +222,7 @@ ANALYZE pagg_tab_ml;
 
 -- For Parallel Append
 SET max_parallel_workers_per_gather TO 2;
+SET parallel_setup_cost = 0;
 
 -- Full aggregation at level 1 as GROUP BY clause matches with PARTITION KEY
 -- for level 1 only. For subpartitions, GROUP BY clause does not match with
@@ -235,6 +236,8 @@ SELECT a, sum(b), array_agg(distinct c), count(*) FROM pagg_tab_ml GROUP BY a HA
 EXPLAIN (COSTS OFF)
 SELECT a, sum(b), array_agg(distinct c), count(*) FROM pagg_tab_ml GROUP BY a HAVING avg(b) < 3;
 
+RESET parallel_setup_cost;
+
 -- Full aggregation at level 1 as GROUP BY clause matches with PARTITION KEY
 -- for level 1 only. For subpartitions, GROUP BY clause does not match with
 -- PARTITION KEY, thus we will have a partial aggregation for them.