From: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
---|---|
To: | Jan Ploski <jpljpl(at)gmx(dot)de> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Creating tons of tables to support a query |
Date: | 2002-09-08 23:36:17 |
Message-ID: | 20020909093617.A9934@svana.org |
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Thread: | |
Lists: | pgsql-general |
On Sun, Sep 08, 2002 at 11:58:44PM +0200, Jan Ploski wrote:
> Hello,
>
> I am in particular wondering, why an index on message(sectionID, dateSent)
> does not make these queries comparably fast:
>
> select msgnum from message where
> sectionID = ? and
> dateSent > ?
> order by dateSent
> limit 1;
>
> select msgnum from scnt_9 where
> dateSent > ?
> order by dateSent
> limit 1;
>
> (scnt_9 is a lookup table which only creates msgnums for messages
> with sectionID == 9)
>
Can you send the results of EXPLAIN ANALYZE for both those queries. Thanks.
--
Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> There are 10 kinds of people in the world, those that can do binary
> arithmetic and those that can't.
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