Received: from localhost (maia-5.hub.org [200.46.204.182]) by postgresql.org (Postfix) with ESMTP id 2B8489FBB8F for ; Thu, 22 Mar 2007 11:36:51 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.182]) (amavisd-new, port 10024) with ESMTP id 64500-03 for ; Thu, 22 Mar 2007 11:36:31 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from relay.icomedias.com (relay.icomedias.com [62.99.232.66]) by postgresql.org (Postfix) with ESMTP id 724E29FBBF9 for ; Thu, 22 Mar 2007 11:36:37 -0300 (ADT) Received: from loki.icomedias.com ([10.192.17.128]) by relay.icomedias.com (8.13.7/8.13.7) with ESMTP id l2MEaWZm030319; Thu, 22 Mar 2007 15:36:33 +0100 From: Mario Weilguni To: pgsql-performance@postgresql.org Subject: Re: Performance of count(*) Date: Thu, 22 Mar 2007 15:36:32 +0100 User-Agent: KMail/1.9.5 Cc: "Jonah H. Harris" , "Merlin Moncure" , "Andreas Tille" References: <36e682920703220733s322788f7i5f89339466c7938c@mail.gmail.com> In-Reply-To: <36e682920703220733s322788f7i5f89339466c7938c@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Message-Id: <200703221536.32575.mweilguni@sime.com> X-Scanned-By: MIMEDefang 2.57 on 10.192.64.104 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200703/321 X-Sequence-Number: 23726 Am Donnerstag, 22. M=C3=A4rz 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...