Received: from localhost (unknown [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id E8A752E01EB for ; Tue, 15 Jan 2008 11:46:15 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-maia, port 10024) with ESMTP id 11109-07 for ; Tue, 15 Jan 2008 11:46:10 -0400 (AST) Received: from mx.comgate.cz (mx.comgate.cz [193.165.185.50]) by postgresql.org (Postfix) with ESMTP id 2A89D2E32DF for ; Tue, 15 Jan 2008 11:46:10 -0400 (AST) Received: from alibaba ([127.0.0.1] helo=[10.1.0.53] ident=root) by mx.comgate.cz with asmtp (Exim 3.35 #1 (Debian)) id 1JEnzF-0001Er-00; Tue, 15 Jan 2008 16:46:01 +0100 Message-ID: <478CD535.6030004@comgate.cz> Date: Tue, 15 Jan 2008 16:45:57 +0100 From: Jakub Ouhrabka User-Agent: Thunderbird 2.0.0.9 (Windows/20071031) MIME-Version: 1.0 To: Tom Lane CC: pgsql-performance@postgresql.org Subject: Re: Linux/PostgreSQL scalability issue - problem with 8 cores References: <7083.1199379570@sss.pgh.pa.us> <477D1D59.7050002@comgate.cz> <4782063C.7070105@comgate.cz> <26502.1199745090@sss.pgh.pa.us> <4782AB4D.8010009@comgate.cz> <27655.1199750492@sss.pgh.pa.us> <47836A4C.5080707@comgate.cz> <10713.1199813111@sss.pgh.pa.us> <47874EE8.2050406@comgate.cz> <12997.1200063940@sss.pgh.pa.us> <478B4BB9.4030208@comgate.cz> <13894.1200324134@sss.pgh.pa.us> <478CA26E.9040105@comgate.cz> <23470.1200410459@sss.pgh.pa.us> In-Reply-To: <23470.1200410459@sss.pgh.pa.us> Content-Type: text/plain; charset=windows-1250; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200801/126 X-Sequence-Number: 28365 > Huh. One transaction truncating a dozen tables? That would match the > sinval trace all right ... It should be 4 tables - the shown log looks like there were more truncates? > You might be throwing the baby out with the bathwater, > performance-wise. Yes, performance was the initial reason to use truncate instead of delete many years ago. But today the truncated tables usualy contain exactly one row - quick measurements now show that it's faster to issue delete instead of truncate in this case. Again, many thanks for your invaluable advice! Kuba