Re: Simple queries take forever to run
От | Shridhar Daithankar |
---|---|
Тема | Re: Simple queries take forever to run |
Дата | |
Msg-id | 3F4E62EC.15091.71172C@localhost обсуждение исходный текст |
Ответ на | Re: Simple queries take forever to run (Michael Guerin <guerin@rentec.com>) |
Список | pgsql-performance |
On 28 Aug 2003 at 10:38, Michael Guerin wrote: > >IN(subquery) is known to run poorly in 7.3.x and earlier. 7.4 is > >generally much better (for reasonably sized subqueries) but in earlier > >versions you'll probably want to convert into an EXISTS or join form. > Something else seems to be going on, even switching to an exists clause > gives much better but poor performance. > count(*) where exists clause: Postgresql 19s, SQL Server <1s > count(*) where not exists: 23.3s SQL Server 1.5s This was with 7.4? Can you try downloading 7.4CVS and try? > > SQL Server runs on a dual 1.4 with 4gigs, win2k > Postgresql runs on a quad 900 with 8 gigs, sunos 5.8 SunOS...Not the impala out there but anyways I would refrain from slipping in that.. Parden me if this is a repeatation, have you set your effective cache size? Bye Shridhar -- Nouvelle cuisine, n.: French for "not enough food".Continental breakfast, n.: English for "not enough food".Tapas, n.: Spanish for "not enough food".Dim Sum, n.: Chinese for more food than you've ever seen in your entire life.
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