Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id EED5964FCD6 for ; Thu, 28 Aug 2008 09:36:55 -0300 (ADT) Received: from postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 87572-06 for ; Thu, 28 Aug 2008 09:36:47 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from lists.commandprompt.com (host-159.commandprompt.net [207.173.203.159]) by postgresql.org (Postfix) with ESMTP id 734A264FCD0 for ; Thu, 28 Aug 2008 09:36:52 -0300 (ADT) Received: from commandprompt.com (CPE001b63afe888-CM001adea9c5a6.cpe.net.cable.rogers.com [99.236.211.160]) (authenticated bits=0) by lists.commandprompt.com (8.13.8/8.13.8) with ESMTP id m7SCdrsw003327 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 28 Aug 2008 05:39:56 -0700 Date: Thu, 28 Aug 2008 08:36:46 -0400 From: Andrew Sullivan To: pgsql-performance@postgresql.org Subject: Re: select on 22 GB table causes "An I/O error occured while sending to the backend." exception Message-ID: <20080828123645.GB23588@commandprompt.com> Mail-Followup-To: Andrew Sullivan , pgsql-performance@postgresql.org References: <82bpze3ou8.fsf@mid.bfk.de> <20080827221338.GP18946@commandprompt.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0 (lists.commandprompt.com [207.173.203.159]); Thu, 28 Aug 2008 05:39:57 -0700 (PDT) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none X-Spam-Level: X-Archive-Number: 200808/368 X-Sequence-Number: 31249 On Wed, Aug 27, 2008 at 03:22:09PM -0700, david@lang.hm wrote: > > I disagree with you. I think goof Postgres operation is so highly dependant > on caching as much data as possible that disabling overcommit (and throwing > away a lot of memory that could be used for cache) is a solution that's as > bad or worse than the problem it's trying to solve. Ok, but the danger is that the OOM killer kills your postmaster. To me, this is a cure way worse than the disease it's trying to treat. YMMD &c. &c. A -- Andrew Sullivan ajs@commandprompt.com +1 503 667 4564 x104 http://www.commandprompt.com/