Re: Performance aggregates
От | snpe |
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Тема | Re: Performance aggregates |
Дата | |
Msg-id | 01051520591903.01497@spnew обсуждение исходный текст |
Ответ на | Re: Performance aggregates (Stephan Szabo <sszabo@megazone23.bigpanda.com>) |
Ответы |
Re: Performance aggregates
|
Список | pgsql-general |
On Tuesday 15 May 2001 17:28, Stephan Szabo wrote: > On Tue, 15 May 2001, snpe wrote: > > Table e_kalkn have 4668 rows and e_kalkns 101170 rows. > > > > Query : > > > > select roba,sum(izn) > > from e_kalkn k,e_kalkns ks > > where k.id=ks.id > > group by roba > > order by roba > > > > is 2.5 times faster on one commercial database (there are tests on > > Internet that say 'Postgresql is faster than that database). > > I can't say which database it is. > > Have you run vacuum analyze (since loading the data) and what does explain > show for the query. Also, what version are you using? I have run : vacuumdb --analyze -v -d mytest I try index on column roba in table e_kalkn, but all is same. This is explain : psql:up1:4: NOTICE: QUERY PLAN: Aggregate (cost=11132.18..11286.42 rows=3085 width=32) -> Group (cost=11132.18..11209.30 rows=30849 width=32) -> Sort (cost=11132.18..11132.18 rows=30849 width=32) -> Hash Join (cost=121.35..8831.95 rows=30849 width=32) -> Seq Scan on e_kalkns ks (cost=0.00..2041.10 rows=101710 width=16) -> Hash (cost=109.68..109.68 rows=4668 width=16) -> Seq Scan on e_kalkn k (cost=0.00..109.68 rows=4668 width=16) EXPLAIN
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