Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 878BD65014E for ; Fri, 29 Aug 2008 01:47:19 -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 08397-02 for ; Fri, 29 Aug 2008 01:46:57 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from westnet.com (westnet.com [216.187.52.2]) by postgresql.org (Postfix) with ESMTP id C710C650170 for ; Fri, 29 Aug 2008 01:46:27 -0300 (ADT) Received: from westnet.com (localhost [127.0.0.1]) by westnet.com (8.14.0/8.14.0) with ESMTP id m7T4jMdn028715; Fri, 29 Aug 2008 00:45:22 -0400 (EDT) Received: from localhost (gsmith@localhost) by westnet.com (8.14.0/8.13.2/Submit) with ESMTP id m7T4jK4M028711; Fri, 29 Aug 2008 00:45:21 -0400 (EDT) X-Authentication-Warning: westnet.com: gsmith owned process doing -bs Date: Fri, 29 Aug 2008 00:45:20 -0400 (EDT) From: Greg Smith X-X-Sender: gsmith@westnet.com To: Bill Moran cc: Matthew Wakeling , pgsql-performance@postgresql.org Subject: Re: select on 22 GB table causes "An I/O error occured while sending to the backend." exception In-Reply-To: <20080828095325.3c95f867.wmoran@collaborativefusion.com> Message-ID: References: <82bpze3ou8.fsf@mid.bfk.de> <20080828095325.3c95f867.wmoran@collaborativefusion.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed 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: 200808/414 X-Sequence-Number: 31295 On Thu, 28 Aug 2008, Bill Moran wrote: > In linux, it's possible to tell the OOM killer never to consider > certain processes for the axe, using /proc magic. See this page: > http://linux-mm.org/OOM_Killer > > Perhaps this should be in the PostgreSQL docs somewhere? The fact that http://www.postgresql.org/docs/current/static/kernel-resources.html#AEN22218 tells you to flat-out turn off overcommit is the right conservative thing to be in the documentation as I see it. Sure, it's possible to keep it on but disable the worst side-effect in some kernels (looks like 2.6.11+, so no RHEL4 for example). Trying to get into all in the manual is kind of pushing what's appropriate for the PostgreSQL docs I think. -- * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD