Hi!
I've checked this thread and examples in it, and do not see stable
improvements
in base tests. Sometimes base tests are considerably slower with patch,
like:
explain analyze
select t1.* from matest0 t1, matest0 t2
where t1.b = t2.b and t2.c = t2.d
order by t1.b limit 10;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=0.46..19.90 rows=10 width=16) (actual time=0.007..0.008
rows=0 loops=1)
-> Merge Join (cost=0.46..181.24 rows=93 width=16) (actual
time=0.007..0.007 rows=0 loops=1)
Merge Cond: (t1.b = t2.b)
-> Merge Append (cost=0.17..90.44 rows=1851 width=16) (actual
time=0.006..0.007 rows=0 loops=1)
Sort Key: t1.b
-> Sort (cost=0.01..0.02 rows=1 width=16) (actual
time=0.004..0.004 rows=0 loops=1)
Sort Key: t1_1.b
Sort Method: quicksort Memory: 25kB
-> Seq Scan on matest0 t1_1 (cost=0.00..0.00 rows=1
width=16) (actual time=0.002..0.002 rows=0 loops=1)
-> Index Scan using matest1i on matest1 t1_2
(cost=0.15..71.90 rows=1850 width=16) (actual time=0.002..0.002 rows=0
loops=1)
-> Materialize (cost=0.29..84.81 rows=10 width=4) (never
executed)
-> Merge Append (cost=0.29..84.78 rows=10 width=4) (never
executed)
Sort Key: t2.b
-> Index Scan using matest0i on matest0 t2_1
(cost=0.12..8.14 rows=1 width=4) (never executed)
Filter: (c = d)
-> Index Scan using matest1i on matest1 t2_2
(cost=0.15..76.53 rows=9 width=4) (never executed)
Filter: (c = d)
Planning Time: 0.252 ms
Execution Time: 0.048 ms
(19 rows)
explain analyze
select t1.* from matest0 t1, matest0 t2
where t1.b = t2.b and t2.c = t2.d
order by t1.b limit 10;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=0.57..20.88 rows=10 width=16) (actual time=0.004..0.004
rows=0 loops=1)
-> Merge Join (cost=0.57..189.37 rows=93 width=16) (actual
time=0.003..0.004 rows=0 loops=1)
Merge Cond: (t1.b = t2.b)
-> Merge Append (cost=0.29..98.56 rows=1851 width=16) (actual
time=0.002..0.003 rows=0 loops=1)
Sort Key: t1.b
-> Index Scan using matest0i on matest0 t1_1
(cost=0.12..8.14 rows=1 width=16) (actual time=0.002..0.002 rows=0 loops=1)
-> Index Scan using matest1i on matest1 t1_2
(cost=0.15..71.90 rows=1850 width=16) (actual time=0.001..0.001 rows=0
loops=1)
-> Materialize (cost=0.29..84.81 rows=10 width=4) (never
executed)
-> Merge Append (cost=0.29..84.78 rows=10 width=4) (never
executed)
Sort Key: t2.b
-> Index Scan using matest0i on matest0 t2_1
(cost=0.12..8.14 rows=1 width=4) (never executed)
Filter: (c = d)
-> Index Scan using matest1i on matest1 t2_2
(cost=0.15..76.53 rows=9 width=4) (never executed)
Filter: (c = d)
Planning Time: 0.278 ms
Execution Time: 0.025 ms
(16 rows)
(patched)
explain analyze
select t1.* from matest0 t1, matest0 t2
where t1.b = t2.b and t2.c = t2.d
order by t1.b limit 10;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=0.46..19.90 rows=10 width=16) (actual time=0.007..0.008
rows=0 loops=1)
-> Merge Join (cost=0.46..181.24 rows=93 width=16) (actual
time=0.007..0.007 rows=0 loops=1)
Merge Cond: (t1.b = t2.b)
-> Merge Append (cost=0.17..90.44 rows=1851 width=16) (actual
time=0.006..0.007 rows=0 loops=1)
Sort Key: t1.b
-> Sort (cost=0.01..0.02 rows=1 width=16) (actual
time=0.004..0.004 rows=0 loops=1)
Sort Key: t1_1.b
Sort Method: quicksort Memory: 25kB
-> Seq Scan on matest0 t1_1 (cost=0.00..0.00 rows=1
width=16) (actual time=0.002..0.002 rows=0 loops=1)
-> Index Scan using matest1i on matest1 t1_2
(cost=0.15..71.90 rows=1850 width=16) (actual time=0.002..0.002 rows=0
loops=1)
-> Materialize (cost=0.29..84.81 rows=10 width=4) (never
executed)
-> Merge Append (cost=0.29..84.78 rows=10 width=4) (never
executed)
Sort Key: t2.b
-> Index Scan using matest0i on matest0 t2_1
(cost=0.12..8.14 rows=1 width=4) (never executed)
Filter: (c = d)
-> Index Scan using matest1i on matest1 t2_2
(cost=0.15..76.53 rows=9 width=4) (never executed)
Filter: (c = d)
Planning Time: 0.252 ms
Execution Time: 0.048 ms
(19 rows)
(vanilla)
explain analyze
select t1.* from matest0 t1, matest0 t2
where t1.b = t2.b and t2.c = t2.d
order by t1.b limit 10;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=0.57..20.88 rows=10 width=16) (actual time=0.004..0.004
rows=0 loops=1)
-> Merge Join (cost=0.57..189.37 rows=93 width=16) (actual
time=0.003..0.004 rows=0 loops=1)
Merge Cond: (t1.b = t2.b)
-> Merge Append (cost=0.29..98.56 rows=1851 width=16) (actual
time=0.002..0.003 rows=0 loops=1)
Sort Key: t1.b
-> Index Scan using matest0i on matest0 t1_1
(cost=0.12..8.14 rows=1 width=16) (actual time=0.002..0.002 rows=0 loops=1)
-> Index Scan using matest1i on matest1 t1_2
(cost=0.15..71.90 rows=1850 width=16) (actual time=0.001..0.001 rows=0
loops=1)
-> Materialize (cost=0.29..84.81 rows=10 width=4) (never
executed)
-> Merge Append (cost=0.29..84.78 rows=10 width=4) (never
executed)
Sort Key: t2.b
-> Index Scan using matest0i on matest0 t2_1
(cost=0.12..8.14 rows=1 width=4) (never executed)
Filter: (c = d)
-> Index Scan using matest1i on matest1 t2_2
(cost=0.15..76.53 rows=9 width=4) (never executed)
Filter: (c = d)
Planning Time: 0.278 ms
Execution Time: 0.025 ms
(16 rows)
--
Nikita Malakhov
Postgres Professional
The Russian Postgres Company
https://postgrespro.ru/
