Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1UpmTe-0002K5-CK for pgsql-performance@arkaria.postgresql.org; Thu, 20 Jun 2013 21:33:10 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1UpmTd-0000TA-RS for pgsql-performance@arkaria.postgresql.org; Thu, 20 Jun 2013 21:33:09 +0000 Received: from makus.postgresql.org ([2001:4800:7903:4::125]) by malur.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1UpmTc-0000Su-M1 for pgsql-performance@postgresql.org; Thu, 20 Jun 2013 21:33:08 +0000 Received: from relay4-d.mail.gandi.net ([217.70.183.196]) by makus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1UpmTZ-0001pb-KA for pgsql-performance@postgresql.org; Thu, 20 Jun 2013 21:33:07 +0000 Received: from mfilter5-d.gandi.net (mfilter5-d.gandi.net [217.70.178.132]) by relay4-d.mail.gandi.net (Postfix) with ESMTP id 3DB59172094; Thu, 20 Jun 2013 23:32:43 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at mfilter5-d.gandi.net Received: from relay4-d.mail.gandi.net ([217.70.183.196]) by mfilter5-d.gandi.net (mfilter5-d.gandi.net [10.0.15.180]) (amavisd-new, port 10024) with ESMTP id BObht9P9KPJr; Thu, 20 Jun 2013 23:32:41 +0200 (CEST) X-Originating-IP: 98.27.58.255 Received: from [192.168.10.146] (cpe-098-027-058-255.nc.res.rr.com [98.27.58.255]) (Authenticated sender: adsend@dunslane.net) by relay4-d.mail.gandi.net (Postfix) with ESMTPSA id B0FAA172080; Thu, 20 Jun 2013 23:32:36 +0200 (CEST) Message-ID: <51C374F2.4050208@dunslane.net> Date: Thu, 20 Jun 2013 17:32:34 -0400 From: Andrew Dunstan User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: sthomas@optionshouse.com CC: Josh Berkus , pgsql-performance@postgresql.org, Greg Smith Subject: Re: PostgreSQL settings for running on an SSD drive References: <51C35E6C.1090705@consistentstate.com> <51C36256.6040502@optionshouse.com> <51C366CE.10206@agliodbs.com> <51C372BA.1040807@optionshouse.com> In-Reply-To: <51C372BA.1040807@optionshouse.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: 0.1 (/) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org On 06/20/2013 05:23 PM, Shaun Thomas wrote: > On 06/20/2013 03:32 PM, Josh Berkus wrote: > >> Did you compare setting RPC to 1.0 vs. setting it to 1.1, or something >> else just slightly higher than SPC? > > Yes, actually. My favored setting when we were on 8.3 was 1.5. But > something with the planner changed pretty drastically when we went to > 9.1, and we were getting some really bad query plans unless we > *strongly* suggested RPC was cheap. I was afraid I'd have to go lower, > but 1 seemed to do the trick. > That would be perverse, surely, but on Fusion-IO RPC = SPC seems to make sense unless you assume that cache misses will be higher for random reads than for sequential reads. cheers andrew -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance