Received: from magus.postgresql.org (magus.postgresql.org [87.238.57.229]) by mail.postgresql.org (Postfix) with ESMTP id DF9061DEB3D6 for ; Mon, 23 Jul 2012 01:38:16 -0300 (ADT) Received: from 173-164-140-181-sfba.hfc.comcastbusiness.net ([173.164.140.181] helo=fetter.org) by magus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1StAPM-0003fM-Hy for pgsql-hackers@postgresql.org; Mon, 23 Jul 2012 04:38:16 +0000 Received: from fetter.org (localhost [127.0.0.1]) by fetter.org (Postfix) with ESMTP id 75EA030088D; Sun, 22 Jul 2012 21:37:47 -0700 (PDT) Received: (from shackle@localhost) by fetter.org (8.14.5/8.14.5/Submit) id q6N4bXvM008326; Sun, 22 Jul 2012 21:37:33 -0700 Date: Sun, 22 Jul 2012 21:37:33 -0700 From: David Fetter To: Tom Lane Cc: Robert Haas , Jeff Janes , pgsql-hackers , Daniel Farina , Craig Ringer , Harold =?iso-8859-1?Q?A=2E_Gim=E9nez?= Subject: Re: Checkpointer split has broken things dramatically (was Re: DELETE vs TRUNCATE explanation) Message-ID: <20120723043733.GA13020@fetter.org> References: <9603.1342454919@sss.pgh.pa.us> <11952.1342456591@sss.pgh.pa.us> <13011.1342457859@sss.pgh.pa.us> <15955.1342466333@sss.pgh.pa.us> <9247.1342565810@sss.pgh.pa.us> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9247.1342565810@sss.pgh.pa.us> User-Agent: Mutt/1.5.21 (2010-09-15) X-Pg-Spam-Score: -0.9 (/) X-Archive-Number: 201207/915 X-Sequence-Number: 211598 On Tue, Jul 17, 2012 at 06:56:50PM -0400, Tom Lane wrote: > Robert Haas writes: > > On Mon, Jul 16, 2012 at 3:18 PM, Tom Lane wrote: > >> BTW, while we are on the subject: hasn't this split completely > >> broken the statistics about backend-initiated writes? > > > Yes, it seems to have done just that. > > This implies that nobody has done pull-the-plug testing on either > HEAD or 9.2 since the checkpointer split went in (2011-11-01), > because even a modicum of such testing would surely have shown that > we're failing to fsync a significant fraction of our write traffic. > > Furthermore, I would say that any performance testing done since > then, if it wasn't looking at purely read-only scenarios, isn't > worth the electrons it's written on. In particular, any performance > gain that anybody might have attributed to the checkpointer splitup > is very probably hogwash. > > This is not giving me a warm feeling about our testing practices. Is there any part of this that the buildfarm, or some other automation framework, might be able to handle? Cheers, David. -- David Fetter http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate