| From: | Ryan Bradetich <rbradetich(at)uswest(dot)net> |
|---|---|
| To: | Josh Berkus <josh(at)agliodbs(dot)com> |
| Cc: | Oleg Lebedev <oleg(dot)lebedev(at)waterford(dot)org>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: slow query |
| Date: | 2003-02-23 21:05:34 |
| Message-ID: | 1046034334.13010.3.camel@beavis.ybsoft.com |
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| Thread: | |
| Lists: | pgsql-performance |
On Sun, 2003-02-23 at 13:52, Josh Berkus wrote:
> Oleg,
>
> > I VACUUM ANALYZED both databases and made sure they have same indexes on
> > the tables.
>
> Have you VACUUM FULL the main database? And how about REINDEX?
>
> > Here is the query:
> > SELECT * FROM media m, speccharacter c
> > WHERE m.mediatype IN (SELECT objectid FROM mediatype WHERE
> > medianame='Audio')
>
> The above should use an EXISTS clause, not IN, unless you are absolutely sure
> that the subquery will never return more than 12 rows.
I am assuming you said this because EXISTS is faster for > 12 rows?
Interesting :)
thanks,
- Ryan
--
Ryan Bradetich <rbradetich(at)uswest(dot)net>
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