X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 932B09DCA0B for ; Fri, 17 Mar 2006 00:24:18 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 15058-02 for ; Fri, 17 Mar 2006 00:24:17 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from mail.Mi8.com (d01gw01.mi8.com [63.240.6.47]) by postgresql.org (Postfix) with ESMTP id 47EF19DC9D7 for ; Fri, 17 Mar 2006 00:24:15 -0400 (AST) Received: from 172.16.1.148 by mail.Mi8.com with ESMTP (- Welcome to Mi8 Corporation www.Mi8.com (D1)); Thu, 16 Mar 2006 23:24:06 -0500 X-Server-Uuid: 241911D6-425B-44B9-A073-E3FE0F8FC774 Received: from MI8NYCMAIL06.Mi8.com ([172.16.1.160]) by D01HOST02.Mi8.com with Microsoft SMTPSVC(6.0.3790.1830); Thu, 16 Mar 2006 23:24:06 -0500 Received: from 69.45.100.3 ([69.45.100.3]) by MI8NYCMAIL06.Mi8.com ( [172.16.1.219]) via Exchange Front-End Server mi8owa.mi8.com ( [172.16.1.118]) with Microsoft Exchange Server HTTP-DAV ; Fri, 17 Mar 2006 04:24:05 +0000 User-Agent: Microsoft-Entourage/11.2.1.051004 Date: Thu, 16 Mar 2006 23:24:00 -0800 Subject: Re: 1 TB of memory From: "Luke Lonergan" To: "Jim Nasby" , pgsql-performance@postgresql.org Message-ID: Thread-Topic: [PERFORM] 1 TB of memory Thread-Index: AcZJKD2QJKPp1kWbQ36iwXaGKbAGBAAZf1muAAFh52Y= In-Reply-To: MIME-Version: 1.0 X-OriginalArrivalTime: 17 Mar 2006 04:24:06.0064 (UTC) FILETIME=[A0E1FB00:01C6497A] X-WSS-ID: 6804E66C2F83778365-01-01 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=1.333 required=5 tests=[AWL=0.080, RCVD_NUMERIC_HELO=1.253] X-Spam-Score: 1.333 X-Spam-Level: * X-Archive-Number: 200603/262 X-Sequence-Number: 17699 Jim, On 3/16/06 10:44 PM, "Luke Lonergan" wrote: > Plus - need more speed? Add 12 more servers, and you'd run at 12.8GB/s and > have 96TB of disk to work with, and you'd *still* spend less on HW and SW > than the SSD. And I forgot to mention that with these 16 servers you'd have 64 CPUs and 256GB of RAM working for you in addition to the 96TB of disk. Every query would use all of that RAM and all of those CPUs, all at the same time. By comparison, with the SSD, you'd have 1 CPU trying to saturate 1 connection to the SSD. If you do anything other than just access the data there (order by, group by, join, aggregation, functions), you'll be faced with trying to have 1 CPU do all the work on 1 TB of data. I suggest that it won't be any faster than having the 1 TB on disk for most queries, as you would be CPU bound. By comparison, with the MPP system, all 64 CPUs would be used at one time to process the N TB of data and if you grew from N TB to 2N TB, you could double the machine size and it would take the same amount of time to do 2N as it did to do N. That's what data parallelism and scaling is all about. Without it, you don't have a prayer of using all 1TB of data in queries. - Luke