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Commitd2bc501

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Expand coverage of parallel gather merge a bit.
Previously paths reaching heap_compare_slots weren't covered.Author: Rushabh LathiaReviewed-By: Andres FreundDiscussion:https://postgr.es/m/CAGPqQf3C+3PBujb+7m=ceWeii4-vBY=XS99LjzrpkpefvzJbFg@mail.gmail.comhttps://postgr.es/m/27200.1502482851@sss.pgh.pa.usBackpatch: 10, where gather merge was introduced
1 parent9f14dc3 commitd2bc501

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2 files changed

+65
-18
lines changed

2 files changed

+65
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lines changed

‎src/test/regress/expected/select_parallel.out

Lines changed: 55 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -258,32 +258,73 @@ select count(*) from tenk1, tenk2 where tenk1.unique1 = tenk2.unique1;
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reset enable_hashjoin;
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reset enable_nestloop;
261-
--test gather merge
262-
set enable_hashaggto off;
261+
--test gather merge
262+
set enable_hashagg= false;
263263
explain (costs off)
264-
select string4,count((unique2)) from tenk1 group bystring4 order by string4;
264+
select count(*) from tenk1 group bytwenty;
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QUERY PLAN
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----------------------------------------------------
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Finalize GroupAggregate
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Group Key:string4
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Group Key:twenty
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-> Gather Merge
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Workers Planned: 4
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-> Partial GroupAggregate
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Group Key:string4
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Group Key:twenty
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-> Sort
274-
Sort Key:string4
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Sort Key:twenty
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-> Parallel Seq Scan on tenk1
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(9 rows)
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278-
select string4, count((unique2)) from tenk1 group by string4 order by string4;
279-
string4 | count
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---------+-------
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AAAAxx | 2500
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HHHHxx | 2500
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OOOOxx | 2500
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VVVVxx | 2500
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(4 rows)
278+
select count(*) from tenk1 group by twenty;
279+
count
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-------
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500
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500
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(20 rows)
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-- gather merge test with 0 worker
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set max_parallel_workers = 0;
305+
explain (costs off)
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select string4 from tenk1 order by string4 limit 5;
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QUERY PLAN
308+
----------------------------------------------
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Limit
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-> Gather Merge
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Workers Planned: 4
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-> Sort
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Sort Key: string4
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-> Parallel Seq Scan on tenk1
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(6 rows)
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select string4 from tenk1 order by string4 limit 5;
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string4
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---------
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AAAAxx
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AAAAxx
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AAAAxx
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AAAAxx
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AAAAxx
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(5 rows)
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327+
reset max_parallel_workers;
287328
reset enable_hashagg;
288329
set force_parallel_mode=1;
289330
explain (costs off)

‎src/test/regress/sql/select_parallel.sql

Lines changed: 10 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -110,14 +110,20 @@ select count(*) from tenk1, tenk2 where tenk1.unique1 = tenk2.unique1;
110110
reset enable_hashjoin;
111111
reset enable_nestloop;
112112

113-
--test gather merge
114-
set enable_hashaggto off;
113+
--test gather merge
114+
set enable_hashagg= false;
115115

116116
explain (costs off)
117-
select string4,count((unique2))from tenk1group bystring4order by string4;
117+
selectcount(*)from tenk1group bytwenty;
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119-
select string4,count((unique2))from tenk1group bystring4order by string4;
119+
selectcount(*)from tenk1group bytwenty;
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-- gather merge test with 0 worker
122+
set max_parallel_workers=0;
123+
explain (costs off)
124+
select string4from tenk1order by string4limit5;
125+
select string4from tenk1order by string4limit5;
126+
reset max_parallel_workers;
121127
reset enable_hashagg;
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set force_parallel_mode=1;

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