Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id 4F96F632D2A for ; Wed, 7 Jul 2010 21:39:27 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 37578-01 for ; Thu, 8 Jul 2010 00:39:19 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id 9AA44632CDB for ; Wed, 7 Jul 2010 21:39:19 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id o680dHkI011691; Wed, 7 Jul 2010 20:39:17 -0400 (EDT) To: Ryan Wexler cc: pgsql-performance@postgresql.org Subject: Re: performance on new linux box In-reply-to: References: Comments: In-reply-to Ryan Wexler message dated "Wed, 07 Jul 2010 16:06:12 -0700" Date: Wed, 07 Jul 2010 20:39:16 -0400 Message-ID: <11690.1278549556@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201007/99 X-Sequence-Number: 39488 Ryan Wexler writes: > Postgresql was previously running on a single cpu linux machine with 2 gigs > of memory and a single sata drive (v8.3). Basically a desktop with linux on > it. I experienced slow performance. > So, I finally moved it to a real server. A dually zeon centos machine with > 6 gigs of memory and raid 10, postgres 8.4. But, I am now experiencing even > worse performance issues. I'm wondering if you moved to a kernel+filesystem version that actually enforces fsync, from one that didn't. If so, the apparently faster performance on the old box was being obtained at the cost of (lack of) crash safety. That probably goes double for your windows-box comparison point. You could try test_fsync from the Postgres sources to confirm that theory, or do some pgbench benchmarking to have more quantifiable numbers. See past discussions about write barriers in this list's archives for more detail. regards, tom lane