From: Richard Huxton <dev@archonet.com>
To: marcelo Cortez <jmdc_marcelo@yahoo.com.ar>
Cc: pgsql-general@postgresql.org
Subject: Re: query optimization
Date: Fri, 12 Aug 2005 17:28:37 +0100
Message-ID: <42FCCE35.1010104@archonet.com> (raw)
In-Reply-To: <20050812161158.93055.qmail@web32615.mail.mud.yahoo.com>
References: <20050812161158.93055.qmail@web32615.mail.mud.yahoo.com>
marcelo Cortez wrote:
> hi guys
>
> i need advice for query optimization,take too long
> time.
> any coments are welcomed :).
Comment 1 - you'll need to post the output of "EXPLAIN ANALYSE", not
just EXPLAIN, otherwise people can't see how long it took.
Comment 2 - you provide the definition of one table but there are about
20 involved in the query.
Comment 3 - likewise for the size of tables.
Comment 4 - you apply a LIMIT without an ORDER BY. Are you sure this is
what you want?
Comment 5 - you don't show any INDEX definitions, so it's difficult to
know whether they are being used.
Comment 6 - Do you know about the genetic query optimiser and thq
geqo_xxx configuration settings?
HTH - come back with the EXPLAIN ANALYSE etc.
--
Richard Huxton
Archonet Ltd
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To: pgsql-general@postgresql.org
Cc: dev@archonet.com, jmdc_marcelo@yahoo.com.ar
Subject: Re: query optimization
In-Reply-To: <42FCCE35.1010104@archonet.com>
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