Received: from localhost (unknown [200.46.204.184]) by developer.postgresql.org (Postfix) with ESMTP id B46792E0045 for ; Fri, 2 May 2008 17:22:45 -0300 (ADT) Received: from developer.postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 04488-02 for ; Fri, 2 May 2008 17:22:28 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from westnet.com (westnet.com [216.187.52.2]) by developer.postgresql.org (Postfix) with ESMTP id 11B2F2E003E for ; Fri, 2 May 2008 17:22:31 -0300 (ADT) Received: from westnet.com (localhost [127.0.0.1]) by westnet.com (8.14.0/8.14.0) with ESMTP id m42KMT0I020699; Fri, 2 May 2008 16:22:29 -0400 (EDT) Received: from localhost (gsmith@localhost) by westnet.com (8.14.0/8.13.2/Submit) with ESMTP id m42KMT8l020694; Fri, 2 May 2008 16:22:29 -0400 (EDT) X-Authentication-Warning: westnet.com: gsmith owned process doing -bs Date: Fri, 2 May 2008 16:22:29 -0400 (EDT) From: Greg Smith X-X-Sender: gsmith@westnet.com To: Alexy Khrabrov cc: pgsql-performance@postgresql.org Subject: Re: two memory-consuming postgres processes In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200805/24 X-Sequence-Number: 29992 On Fri, 2 May 2008, Alexy Khrabrov wrote: > I have an UPDATE query updating a 100 million row table, and > allocate enough memory via shared_buffers=1500MB. In addition to reducing that as you've been advised, you'll probably need to increase checkpoint_segments significantly from the default (3) in order to get good performance on an update that large. Something like 30 would be a reasonable starting point. I'd suggest doing those two things, seeing how things go, and reporting back if you still think performance is unacceptable. We'd need to know your PostgreSQL version in order to really target future suggestions. -- * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD