Re: slow query

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От Ryan Bradetich
Тема Re: slow query
Дата
Msg-id 1046034334.13010.3.camel@beavis.ybsoft.com
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Ответ на Re: slow query  (Josh Berkus <josh@agliodbs.com>)
Ответы Re: slow query
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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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