Received: from localhost (unknown [200.46.204.183])
	by postgresql.org (Postfix) with ESMTP id 6D0239F9E50
	for <pgsql-performance-postgresql.org@postgresql.org>;
	Sat,  6 Oct 2007 02:50:18 -0300 (ADT)
Received: from postgresql.org ([200.46.204.71])
	by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024)
	with ESMTP id 11358-07 for
	<pgsql-performance-postgresql.org@postgresql.org>;
	Sat,  6 Oct 2007 02:50:13 -0300 (ADT)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.5
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
	by postgresql.org (Postfix) with ESMTP id 325E89F9535
	for <pgsql-performance@postgresql.org>;
	Sat,  6 Oct 2007 02:50:13 -0300 (ADT)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
	by sss.pgh.pa.us (8.14.1/8.14.1) with ESMTP id l965o3Qa011262;
	Sat, 6 Oct 2007 01:50:03 -0400 (EDT)
To: "Jeff Frost" <jeff@frostconsultingllc.com>
cc: "'PostgreSQL Performance'" <pgsql-performance@postgresql.org>
Subject: Re: query plan worse after analyze 
In-reply-to: <029201c807bc$f1642f60$120a0a0a@jefflap> 
References: <029201c807bc$f1642f60$120a0a0a@jefflap>
Comments: In-reply-to "Jeff Frost" <jeff@frostconsultingllc.com>
	message dated "Fri, 05 Oct 2007 19:02:26 -0700"
Date: Sat, 06 Oct 2007 01:50:03 -0400
Message-ID: <11261.1191649803@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: Maia Mailguard 1.0.1
X-Archive-Number: 200710/67
X-Sequence-Number: 27089

"Jeff Frost" <jeff@frostconsultingllc.com> writes:
> Before analyze it seems to choose Bitmap Heap Scan on episodes
> current_episode, but after it chooses Index Scan Backward using
> index_episodes_on_publish_on on episodes current_episode.

Have you tried raising the stats target for "episodes"?  Seems like
the problem is a misestimate of the frequency of matches for
season_id = something.

			regards, tom lane