Received: from localhost (unknown [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id B20962E0049; Sun, 9 Dec 2007 21:49:20 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.187]) (amavisd-maia, port 10024) with ESMTP id 16302-05; Sun, 9 Dec 2007 21:49:04 -0400 (AST) Received: from lists.commandprompt.com (host-159.commandprompt.net [207.173.203.159]) by postgresql.org (Postfix) with ESMTP id 688942E006B; Sun, 9 Dec 2007 21:49:09 -0400 (AST) Received: from perhan.alvh.no-ip.org (200-126-109-160.bk7-dsl.surnet.cl [200.126.109.160]) (authenticated bits=0) by lists.commandprompt.com (8.13.8/8.13.8) with ESMTP id lBA1n1ck005945 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sun, 9 Dec 2007 17:49:05 -0800 Received: by perhan.alvh.no-ip.org (Postfix, from userid 1000) id A551247C7E; Sun, 9 Dec 2007 22:48:39 -0300 (CLST) Date: Sun, 9 Dec 2007 22:48:39 -0300 From: Alvaro Herrera To: Greg Smith Cc: pgsql-docs@postgresql.org, pgsql-hackers@postgresql.org Subject: Re: [HACKERS] "distributed checkpoint" Message-ID: <20071210014839.GA7240@alvh.no-ip.org> References: <20071206220348.GM8451@alvh.no-ip.org> <5958.1196991889@sss.pgh.pa.us> <20071206191944.1d7926d2@commandprompt.com> <20071207034328.GB18310@fetter.org> <1197051730.4255.603.camel@ebony.site> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0 (lists.commandprompt.com [207.173.203.159]); Sun, 09 Dec 2007 17:49:05 -0800 (PST) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200712/39 X-Sequence-Number: 4707 Greg Smith wrote: > It's good this came up, because that is factually wrong; while the average > case is much better some OS-dependant aspects of the spike (what happens at > fsync) are certainly still there. I think it's easier to rewrite this > whole thing so it's technically accurate rather than a simple fix of the > wording, something like this: > > "Checkpoint writes can be spread over a longer time period to smooth the > I/O spike during each checkpoint" Thanks, I changed it to this. -- Alvaro Herrera http://www.advogato.org/person/alvherre "No necesitamos banderas No reconocemos fronteras" (Jorge González)