To: "Dawid Kuroczko" <qnex42@gmail.com>,
	"Postgresql Performance" <pgsql-performance@postgresql.org>
Subject: Re: Planner doesn't look at LIMIT?
References: <758d5e7f0507220210bfa4978@mail.gmail.com>
Message-ID: <op.subgiji7th1vuj@localhost>
Date: Fri, 22 Jul 2005 15:16:57 +0200
From: PFC <lists@boutiquenumerique.com>
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	Which row do you want ? Do you want 'a row' at random ?
	I presume you want the N latest rows ?
	In that case you should use an ORDER BY on an indexed field, the serial  
primary key will do nicely (ORDER BY id DESC) ; it's indexed so it will  
use the index and it will fly.

> Any ideas how to make it work (other than rewriting the query to use
> subselects, use explicit id-rows, disabling hashjoin completely)?
> Or is this a bug?
>
>    Regards,
>       Dawid
>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
>        choose an index scan if your joining column's datatypes do not
>        match
>