From: Ryan Bradetich <rbradetich@uswest.net>
To: Josh Berkus <josh@agliodbs.com>
Cc: Oleg Lebedev <oleg.lebedev@waterford.org>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: slow query
Date: 23 Feb 2003 14:05:34 -0700
Message-ID: <1046034334.13010.3.camel@beavis.ybsoft.com> (raw)
In-Reply-To: <200302231252.30681.josh@agliodbs.com>
References: <993DBE5B4D02194382EC8DF8554A5273033583@postoffice.waterford.org>
<200302231252.30681.josh@agliodbs.com>
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@uswest.net>
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To: pgsql-performance@postgresql.org
Cc: rbradetich@uswest.net, josh@agliodbs.com, oleg.lebedev@waterford.org
Subject: Re: slow query
In-Reply-To: <1046034334.13010.3.camel@beavis.ybsoft.com>
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