Received: from localhost (maia-1.hub.org [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id B679D9FB611 for ; Thu, 22 Mar 2007 12:16:35 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-new, port 10024) with ESMTP id 23963-01-10 for ; Thu, 22 Mar 2007 12:15:57 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from heaven.kostyrka.org (h1634.serverkompetenz.net [81.169.154.44]) by postgresql.org (Postfix) with ESMTP id CBB0A9FBD15 for ; Thu, 22 Mar 2007 12:15:53 -0300 (ADT) Received: from localhost (localhost [127.0.0.1]) by heaven.kostyrka.org (Postfix) with ESMTP id 3C8A74FB8A; Thu, 22 Mar 2007 16:15:51 +0100 (CET) Received: from heaven.kostyrka.org ([127.0.0.1]) by localhost (heaven.kostyrka.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 03215-04; Thu, 22 Mar 2007 16:15:51 +0100 (CET) Received: from andi-lap (localhost [127.0.0.1]) by heaven.kostyrka.org (Postfix) with SMTP id 07AB64FB88; Thu, 22 Mar 2007 16:15:48 +0100 (CET) Received: by andi-lap (sSMTP sendmail emulation); Thu, 22 Mar 2007 16:17:17 +0100 Date: Thu, 22 Mar 2007 16:17:17 +0100 From: Andreas Kostyrka To: Mario Weilguni Cc: pgsql-performance@postgresql.org, "Jonah H. Harris" , Merlin Moncure , Andreas Tille Subject: Re: Performance of count(*) Message-ID: <20070322151714.GA11448@andi-lap.la.revver.com> References: <36e682920703220733s322788f7i5f89339466c7938c@mail.gmail.com> <200703221536.32575.mweilguni@sime.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <200703221536.32575.mweilguni@sime.com> User-Agent: mutt-ng/devel-r804 (Debian) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200703/329 X-Sequence-Number: 23734 * Mario Weilguni [070322 15:59]: > Am Donnerstag, 22. März 2007 15:33 schrieb Jonah H. Harris: > > On 3/22/07, Merlin Moncure wrote: > > > As others suggest select count(*) from table is very special case > > > which non-mvcc databases can optimize for. > > > > Well, other MVCC database still do it faster than we do. However, I > > think we'll be able to use the dead space map for speeding this up a > > bit wouldn't we? > > Which MVCC DB do you mean? Just curious... Well, mysql claims InnoDB to be mvcc ;) Andreas