Received: from localhost (unknown [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id 77F212E2FD0 for ; Thu, 3 Jan 2008 13:37:45 -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 21166-04 for ; Thu, 3 Jan 2008 13:37:33 -0400 (AST) Received: from mx.comgate.cz (mx.comgate.cz [193.165.185.50]) by postgresql.org (Postfix) with ESMTP id AF5CC2E01E7 for ; Thu, 3 Jan 2008 13:37:39 -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 1JAU0Z-0007HN-00; Thu, 03 Jan 2008 18:37:31 +0100 Message-ID: <477D1D59.7050002@comgate.cz> Date: Thu, 03 Jan 2008 18:37:29 +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> In-Reply-To: <7083.1199379570@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: 200801/8 X-Sequence-Number: 28247 Hi Tom, > Interesting. Maybe you could use oprofile to try to see what's > happening? It sounds a bit like momentary contention for a spinlock, > but exactly what isn't clear. ok, we're going to try oprofile, will let you know... > Perhaps. Have you tried logging executions of NOTIFY to see if they > are correlated with the spikes? We didn't log the notifies but I think it's not correlated. We'll have a detailed look next time we try it (with oprofile). Thanks for suggestions! Kuba