Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 1584837BA27 for ; Mon, 29 Sep 2008 00:47:17 -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 19871-08 for ; Mon, 29 Sep 2008 00:47:14 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from gatekeeper.Mib-infotech.co.nz (60-234-154-229.bitstream.orcon.net.nz [60.234.154.229]) by postgresql.org (Postfix) with ESMTP id E042837B9B1 for ; Mon, 29 Sep 2008 00:47:13 -0300 (ADT) Received: from localhost (localhost [127.0.0.1]) by gatekeeper.Mib-infotech.co.nz (Postfix) with ESMTP id 4DFF810C6EF; Mon, 29 Sep 2008 16:47:11 +1300 (NZDT) X-Virus-Scanned: amavisd-new at mib-infotech.co.nz Received: from gatekeeper.Mib-infotech.co.nz ([127.0.0.1]) by localhost (gatekeeper.mib-infotech.co.nz [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id QsF6wCAzqPQ2; Mon, 29 Sep 2008 16:47:09 +1300 (NZDT) Received: from [192.168.95.202] (mr-creosote.mib-infotech.co.nz [192.168.95.202]) by gatekeeper.Mib-infotech.co.nz (Postfix) with ESMTPA id 3A3CB10C6EE; Mon, 29 Sep 2008 16:47:09 +1300 (NZDT) Message-ID: <48E04FBD.9030304@mib-infotech.co.nz> Date: Mon, 29 Sep 2008 16:47:09 +1300 From: John Huttley User-Agent: Thunderbird 2.0.0.16 (Windows/20080708) MIME-Version: 1.0 To: Dan Langille CC: pgsql-performance@postgresql.org Subject: Re: Slow updates, poor IO References: <48DBE587.3050406@mib-infotech.co.nz> <20080926131556.GA1005@commandprompt.com> <48DD6A4A.10209@mib-infotech.co.nz> <48DEB4D4.1020100@mib-infotech.co.nz> <6110.1222612388@sss.pgh.pa.us> <48DFFCDB.3020000@mib-infotech.co.nz> <48E003AC.5000306@mib-infotech.co.nz> <48E036F4.3040609@mib-infotech.co.nz> <1DFA2F1D-56D0-46B1-B9E1-27E994822FF4@langille.org> In-Reply-To: <1DFA2F1D-56D0-46B1-B9E1-27E994822FF4@langille.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=1.715 tagged_above=0 required=5 tests=RCVD_IN_SORBS_DUL=1.615, RDNS_DYNAMIC=0.1 X-Spam-Level: * X-Archive-Number: 200809/251 X-Sequence-Number: 31564 I've canned the db and got rid my of data. I'm in the midst of doing some other benchmarking for a possible change to the bacula database. Loading up 1M records into a table of 60M records complete with indexes. It's still going... --john Dan Langille wrote: > > On Sep 28, 2008, at 10:01 PM, John Huttley wrote: > >> >> >> Greg Smith wrote: >>> On Mon, 29 Sep 2008, John Huttley wrote: >>> >>>> checkpoint _segments=16 is fine, going to 64 made no improvement. >>> >>> You might find that it does *after* increasing shared_buffers. If >>> the buffer cache is really small, the checkpoints can't have very >>> much work to do, so their impact on performance is smaller. Once >>> you've got a couple of hundred MB on there, the per-checkpoint >>> overhead can be considerable. >>> >> Ahh bugger, I've just trashed my test setup. > > Pardon? How did you do that? >