Received: from localhost.localdomain (postgresql.org [64.49.215.8])
	by localhost (Postfix) with ESMTP id E9BBD476E64
	for <pgsql-sql@postgresql.org>; Thu, 27 Jun 2002 23:57:34 -0400 (EDT)
Mailbox-Line: From tgl@sss.pgh.pa.us  Thu Jun 27 23:57:34 2002
Received: from sss.pgh.pa.us (unknown [192.204.191.242])
	by postgresql.org (Postfix) with ESMTP id 9864D476993
	for <pgsql-sql@postgresql.org>; Thu, 27 Jun 2002 23:54:51 -0400 (EDT)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
	by sss.pgh.pa.us (8.11.4/8.11.4) with ESMTP id g5S3qej02370;
	Thu, 27 Jun 2002 23:52:40 -0400 (EDT)
To: Keith Gray <keith@heart.com.au>
Cc: Masaru Sugawara <rk73@sea.plala.or.jp>,
	Alvar Freude <alvar@a-blast.org>, pgsql-sql@postgresql.org
Subject: Re: 2 Selects 1 is faster, why? 
In-reply-to: <3D1BA27E.9000802@heart.com.au> 
References: <afag3c$kce$1@news.hub.org>
	<1371510000.1025105687@gnarzelwicht.delirium-arts.de>
	<20020627234531.7ECB.RK73@sea.plala.or.jp>
	<3D1BA27E.9000802@heart.com.au>
Comments: In-reply-to Keith Gray <keith@heart.com.au>
	message dated "Fri, 28 Jun 2002 09:40:46 +1000"
Date: Thu, 27 Jun 2002 23:52:40 -0400
Message-ID: <2367.1025236360@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Spam-Status: No, hits=-5.4 required=5.0
	tests=IN_REP_TO,X_NOT_PRESENT,SUBJ_ENDS_IN_Q_MARK version=2.30
X-Spam-Level: 
X-Archive-Number: 200206/379
X-Sequence-Number: 8344

Keith Gray <keith@heart.com.au> writes:
> ...but is it true that if you place the filter clause first,
> the join will not have to complete the whole table?

PG's planner does not pay attention to the ordering of WHERE clauses;
it will do what it thinks best with them in any case.

			regards, tom lane