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Expand coverage of parallel gather merge a bit.

Browse source 
Previously paths reaching heap_compare_slots weren't covered.

Author: Rushabh Lathia
Reviewed-By: Andres Freund
Discussion:
	https://postgr.es/m/CAGPqQf3C+3PBujb+7m=ceWeii4-vBY=XS99LjzrpkpefvzJbFg@mail.gmail.com
	https://postgr.es/m/27200.1502482851@sss.pgh.pa.us
Backpatch: 10, where gather merge was introduced
This commit is contained in:
Andres Freund 2017-08-14 15:21:26 -07:00
parent 9f14dc393b
commit d2bc501573
2 changed files with 65 additions and 18 deletions
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69
src/test/regress/expected/select_parallel.out
View file

@ -258,32 +258,73 @@ select count(*) from tenk1, tenk2 where tenk1.unique1 = tenk2.unique1;
reset enable_hashjoin;
reset enable_nestloop;
--test gather merge
set enable_hashagg to off;
-- test gather merge
set enable_hashagg = false;
explain (costs off)
select string4, count((unique2)) from tenk1 group by string4 order by string4;
select count(*) from tenk1 group by twenty;
QUERY PLAN
----------------------------------------------------
Finalize GroupAggregate
Group Key: string4
Group Key: twenty
-> Gather Merge
Workers Planned: 4
-> Partial GroupAggregate
Group Key: string4
Group Key: twenty
-> Sort
Sort Key: string4
Sort Key: twenty
-> Parallel Seq Scan on tenk1
(9 rows)
select string4, count((unique2)) from tenk1 group by string4 order by string4;
string4 | count
---------+-------
AAAAxx | 2500
HHHHxx | 2500
OOOOxx | 2500
VVVVxx | 2500
(4 rows)
select count(*) from tenk1 group by twenty;
count
-------
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
(20 rows)
-- gather merge test with 0 worker
set max_parallel_workers = 0;
explain (costs off)
select string4 from tenk1 order by string4 limit 5;
QUERY PLAN
----------------------------------------------
Limit
-> Gather Merge
Workers Planned: 4
-> Sort
Sort Key: string4
-> Parallel Seq Scan on tenk1
(6 rows)
select string4 from tenk1 order by string4 limit 5;
string4
---------
AAAAxx
AAAAxx
AAAAxx
AAAAxx
AAAAxx
(5 rows)
reset max_parallel_workers;
reset enable_hashagg;
set force_parallel_mode=1;
explain (costs off)

14
src/test/regress/sql/select_parallel.sql
View file

@ -110,14 +110,20 @@ select count(*) from tenk1, tenk2 where tenk1.unique1 = tenk2.unique1;
reset enable_hashjoin;
reset enable_nestloop;
--test gather merge
set enable_hashagg to off;
-- test gather merge
set enable_hashagg = false;
explain (costs off)
select string4, count((unique2)) from tenk1 group by string4 order by string4;
select count(*) from tenk1 group by twenty;
select string4, count((unique2)) from tenk1 group by string4 order by string4;
select count(*) from tenk1 group by twenty;
-- gather merge test with 0 worker
set max_parallel_workers = 0;
explain (costs off)
select string4 from tenk1 order by string4 limit 5;
select string4 from tenk1 order by string4 limit 5;
reset max_parallel_workers;
reset enable_hashagg;
set force_parallel_mode=1;