Received: from maia.hub.org (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 587E663432D for ; Mon, 9 Nov 2009 12:04:46 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 72049-03 for ; Mon, 9 Nov 2009 16:04:35 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from viefep13-int.chello.at (viefep13-int.chello.at [62.179.121.33]) by mail.postgresql.org (Postfix) with ESMTP id 58EB2634367 for ; Mon, 9 Nov 2009 12:04:10 -0400 (AST) Received: from edge03.upc.biz ([192.168.13.238]) by viefep13-int.chello.at (InterMail vM.7.09.01.00 201-2219-108-20080618) with ESMTP id <20091109160408.MHFX16274.viefep13-int.chello.at@edge03.upc.biz>; Mon, 9 Nov 2009 17:04:08 +0100 Received: from laci.sznet ([80.99.119.49]) by edge03.upc.biz with edge id 34451d06k1429wY03446XK; Mon, 09 Nov 2009 17:04:08 +0100 X-SourceIP: 80.99.119.49 Message-ID: <4AF83D74.4030503@shopzeus.com> Date: Mon, 09 Nov 2009 17:04:04 +0100 From: Laszlo Nagy User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Robert Haas CC: pgsql-performance Subject: Re: random_page_cost for tablespace References: <4AF81207.4050008@shopzeus.com> <603c8f070911090548g40d42a1erdbe262c545612739@mail.gmail.com> In-Reply-To: <603c8f070911090548g40d42a1erdbe262c545612739@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: 8bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-0.74 tagged_above=-10 required=5 tests=BAYES_20=-0.74 X-Spam-Level: X-Archive-Number: 200911/94 X-Sequence-Number: 36262 Robert Haas írta: > 2009/11/9 Laszlo Nagy : > >> We have a bigger table with some million rows. Number of index scans is >> high, number of seq reads is low. This table if often joined with >> others... so we want to buy a new SSD drive, create a tablespace on it >> and put this big table on it. Random read speed on SSD is identical to >> seq read. However, I need to tell the optimizer that random_page_cost is >> less for the new tablespace. Is there a way to do it? >> > > I happen to be working on a patch for this exact feature. However, > even assuming it gets in, that means waiting for 8.5. > That will be a very nice feature. Thank you! :-)