X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org
Received: from localhost (mx1.hub.org [200.46.208.251])
	by postgresql.org (Postfix) with ESMTP id 1C9D59F9430;
	Wed, 10 May 2006 12:59:27 -0300 (ADT)
Received: from postgresql.org ([200.46.204.71])
	by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024)
	with ESMTP id 19953-09; Wed, 10 May 2006 12:59:17 -0300 (ADT)
X-Greylist: from auto-whitelisted by SQLgrey-
X-Greylist: from auto-whitelisted by SQLgrey-
Received: from mail.logix-tt.com (unknown [212.211.145.186])
	by postgresql.org (Postfix) with ESMTP id 254389F9D82;
	Wed, 10 May 2006 12:59:17 -0300 (ADT)
Received: from kingfisher.intern.logix-tt.com (p549D13DA.dip0.t-ipconnect.de
	[84.157.19.218])
	(using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
	(No client certificate requested)
	by mail.logix-tt.com (Postfix) with ESMTP id 591D965837;
	Wed, 10 May 2006 18:00:28 +0200 (CEST)
Received: from [127.0.0.1] (localhost [127.0.0.1])
	by kingfisher.intern.logix-tt.com (Postfix) with ESMTP id CF136181520E4;
	Wed, 10 May 2006 17:59:27 +0200 (CEST)
Message-ID: <44620DDE.1080500@logix-tt.com>
Date: Wed, 10 May 2006 17:59:26 +0200
From: Markus Schaber <schabi@logix-tt.com>
Organization: Logical Tracking and Tracing International AG, Switzerland
User-Agent: Debian Thunderbird 1.0.7 (X11/20051017)
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: pgsql-performance@postgresql.org
Cc: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] Big IN() clauses etc : feature proposal
References: <1147110142.32369.7.camel@archimedes>
	<20060508175013.GY99570@pervasive.com>
	<28288.1147111196@sss.pgh.pa.us> <op.s89zl30wcigqcu@apollo13>
	<20060509105214.P90693@vesihiisi.cksoft.de>
	<op.s8916gm6cigqcu@apollo13>
	<758d5e7f0605090943p1bbfdae2p4cb28ba128288316@mail.gmail.com>
	<op.s9amckxhcigqcu@apollo13> <4461EAAC.7030105@logix-tt.com>
	<op.s9cayhotcigqcu@apollo13> <20060510145551.GB14476@svana.org>
	<446206FF.7050603@superlativ.dk>
In-Reply-To: <446206FF.7050603@superlativ.dk>
X-Enigmail-Version: 0.93.0.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
X-Virus-Scanned: Maia Mailguard 1.0.1
X-Archive-Number: 200605/264
X-Sequence-Number: 19051

Hi, Nils,

Nis Jorgensen wrote:

> It will probably be quite common for the number to depend on the number
> of rows in other tables. Even if this is fairly constant within one db
> (some assumption), it is likely to be different in others using the same
> function definition. Perhaps a better solution would be to cache the
> result of the estimator function.

Sophisticated estimator functions are free to use the pg_statistics
views for their row count estimation.


HTH,
Markus
-- 
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf.     | Software Development GIS

Fight against software patents in EU! www.ffii.org www.nosoftwarepatents.org