Received: from localhost (maia-4.hub.org [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id D02D19FB4D9 for ; Wed, 6 Jun 2007 04:30:03 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 11457-03 for ; Wed, 6 Jun 2007 04:30:00 -0300 (ADT) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.5 Received: from hu-out-0506.google.com (hu-out-0506.google.com [72.14.214.234]) by postgresql.org (Postfix) with ESMTP id DD4C49FB450 for ; Wed, 6 Jun 2007 04:29:59 -0300 (ADT) Received: by hu-out-0506.google.com with SMTP id 22so23799hug for ; Wed, 06 Jun 2007 00:29:58 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding:sender; b=SngpRpu7uY2joSdxOveZdl7MME6UQb+0ZBximpCp7xwc9+6wicxZWkew3pD71Sp6Zbb+HfDMV70WD3aiAAHxguyTZc3wL47yBI+SyuwwqA3L5HakzgBftX80YssXylnBHV5eH68Pm0k2jfCHIhLLH+Sw9sXxN8zptTqBzspKLSg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding:sender; b=gNTNdmv8cfw7Tb3PcIjAQhKfsDigboNP54MzzkiVbIjd60H+XM57UGskm32U2SbkZ842V8cP+yEomxAGeXgIQObsENzSFieF9n8nyJGHIB/hhylMu1Wgt+X10vv37hPaiuEqgLPZOat9Pj6QbGxbcYX4QwotWwIyaq3BhuK+iCg= Received: by 10.66.249.16 with SMTP id w16mr1060809ugh.1181114998208; Wed, 06 Jun 2007 00:29:58 -0700 (PDT) Received: from ?192.168.1.33? ( [82.3.233.102]) by mx.google.com with ESMTP id l22sm266284uga.2007.06.06.00.29.56 (version=SSLv3 cipher=RC4-MD5); Wed, 06 Jun 2007 00:29:56 -0700 (PDT) Message-ID: <4666625F.9010308@enterprisedb.com> Date: Wed, 06 Jun 2007 08:29:35 +0100 From: Heikki Linnakangas User-Agent: Icedove 1.5.0.10 (X11/20070329) MIME-Version: 1.0 To: david@lang.hm CC: "Steinar H. Gunderson" , pgsql-performance@postgresql.org Subject: Re: Thousands of tables versus on table? References: <1180980943.31471.322.camel@archimedes> <46645DD9.7030805@soliantconsulting.com> <877iqjmro5.fsf@oxford.xeocode.com> <46647427.4030103@g2switchworks.com> <466593E5.1010904@g2switchworks.com> <87sl96z0wf.fsf@oxford.xeocode.com> <10525.1181080765@sss.pgh.pa.us> <20070605220609.GA9835@uio.no> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200706/89 X-Sequence-Number: 25122 david@lang.hm wrote: > On Wed, 6 Jun 2007, Steinar H. Gunderson wrote: > >> On Tue, Jun 05, 2007 at 05:59:25PM -0400, Tom Lane wrote: >>> I think the main argument for partitioning is when you are interested in >>> being able to drop whole partitions cheaply. >> >> Wasn't there also talk about adding the ability to mark individual >> partitions >> as read-only, thus bypassing MVCC and allowing queries to be satisfied >> using >> indexes only? >> >> Not that I think I've seen it on the TODO... :-) > > now that's a very interesting idea, especially when combined with > time-based data where the old times will never change. That's been discussed, but it's controversial. IMHO a better way to achieve that is to design the dead-space-map so that it can be used to check which parts of a table are visible to everyone, and skip visibility checks. That doesn't require any user action, and allows updates. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com