Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id 669051337B71 for ; Tue, 26 Oct 2010 20:49:41 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 96192-08 for ; Tue, 26 Oct 2010 23:49:35 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from eagle.jhcloos.com (eagle.jhcloos.com [207.210.242.212]) by mail.postgresql.org (Postfix) with ESMTP id 6C4641337B58 for ; Tue, 26 Oct 2010 20:49:33 -0300 (ADT) Received: by eagle.jhcloos.com (Postfix, from userid 10) id 5D6AB400E5; Tue, 26 Oct 2010 23:49:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jhcloos.com; s=eagle; t=1288136972; bh=zUS1gG2qtX2/CjWavjyzi7W06JxtUCgihadtVMfZ0Dk=; h=From:To:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=wspB0DKyC040ay/JFvi+XBErACIelg+kG616sCRGyoILY8yKmwn21zQrwSEvxDFEG CKHJpZ4dGu97B4wQEsSUWEnUoldTnhr+u888Y3DaEyx2ubYKlDUzb4MZyxD2dqi2XE JPYaGR6EImxv3DWn+4N0NOvCscvR47bKX9gH4fdk= Received: from carbon (localhost [127.0.0.1]) by carbon.jhcloos.org (Postfix) with ESMTP id 742491E8D12 for ; Tue, 26 Oct 2010 23:45:12 +0000 (UTC) From: James Cloos To: pgsql-performance@postgresql.org Subject: Re: CPUs for new databases In-Reply-To: <4CC73FEF.9020805@agliodbs.com> (Josh Berkus's message of "Tue, 26 Oct 2010 13:54:07 -0700") References: <4CC6CFAA.10107@one.com> <4CC73FEF.9020805@agliodbs.com> User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/24.0.50 (gnu/linux) Face: iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABHNCSVQICAgIfAhkiAAAAI1J REFUOE+lU9ESgCAIg64P1y+ngUdxhl5H8wFbbM0OmUiEhKkCYaZThXCo6KE5sCbA1DDX3genvO4d eBQgEMaM5qy6uWk4SfBYfdu9jvBN9nSVDOKRtwb+I3epboOsOX5pZbJNsBJFvmQQ05YMfieIBnYX FK2N6dOawd97r/e8RjkTLzmMsiVgrAoEugtviCM3v2WzjgAAAABJRU5ErkJggg== Copyright: Copyright 2009 James Cloos OpenPGP: ED7DAEA6; url=http://jhcloos.com/public_key/0xED7DAEA6.asc OpenPGP-Fingerprint: E9E9 F828 61A4 6EA9 0F2B 63E7 997A 9F17 ED7D AEA6 Date: Tue, 26 Oct 2010 19:45:12 -0400 Message-ID: Lines: 25 MIME-Version: 1.0 Content-Type: text/plain X-Hashcash: 1:30:101026:pgsql-performance@postgresql.org::HH8foYaROYhM5Tu9:0000000000000000000000000000Rbw25 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201010/452 X-Sequence-Number: 40870 >>>>> "JB" == Josh Berkus writes: JB> In a general workload, fewer faster cores are better. We do not scale JB> perfectly across cores. The only case where that's not true is JB> maintaining lots of idle connections, and that's really better dealt JB> with in software. I've found that ram speed is the most limiting factor I've run into for those cases where the db fits in RAM. The less efficient lookups run just as fast when the CPU is in powersving mode as in performance, which implies that the cores are mostly waiting on RAM (cache or main). I suspect cache size and ram speed will be the most important factors until the point where disk i/o speed and capacity take over. I'm sure some db applications run computaionally expensive queries on the server, but most queries seem light on computaion and heavy on gathering and comparing. It can help to use recent versions of gcc with -march=native. And recent versions of glibc offer improved string ops on recent hardware. -JimC -- James Cloos OpenPGP: 1024D/ED7DAEA6