Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 6839364FCD9 for ; Mon, 15 Sep 2008 05:37:01 -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 09160-05 for ; Mon, 15 Sep 2008 05:36:46 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from mx01.bfk.de (mx01.bfk.de [193.227.124.2]) by postgresql.org (Postfix) with ESMTP id 933F364FCC9 for ; Mon, 15 Sep 2008 05:36:45 -0300 (ADT) Received: from mx00.int.bfk.de ([10.119.110.2]) by mx01.bfk.de with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) id 1Kf9ZP-0004pU-93; Mon, 15 Sep 2008 10:36:31 +0200 Received: from fweimer by bfk.de with local id 1Kf9ZY-0003w0-3E; Mon, 15 Sep 2008 10:36:40 +0200 To: Craig James Cc: PostgreSQL Performance , Matthew Wakeling Subject: Re: select on 22 GB table causes "An I/O error occured while sending to the backend." exception References: <82bpze3ou8.fsf@mid.bfk.de> <48B6EA7E.2090707@emolecules.com> From: Florian Weimer Date: Mon, 15 Sep 2008 10:36:40 +0200 In-Reply-To: <48B6EA7E.2090707@emolecules.com> (Craig James's message of "Thu, 28 Aug 2008 11:12:14 -0700") Message-ID: <82d4j5ls9z.fsf@mid.bfk.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable 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: 200809/170 X-Sequence-Number: 31483 * Craig James: > So it never makes sense to enable overcommitted memory when > Postgres, or any server, is running. There are some run-time environments which allocate huge chunks of memory on startup, without marking them as not yet in use. SBCL is in this category, and also the Hotspot VM (at least some extent). --=20 Florian Weimer BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstra=DFe 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99