Received: from localhost (unknown [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id 858602E33AD for ; Thu, 29 Nov 2007 16:22:23 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-maia, port 10024) with ESMTP id 76897-09 for ; Thu, 29 Nov 2007 16:22:19 -0400 (AST) Received: from smtp160.sat.emailsrvr.com (smtp160.sat.emailsrvr.com [66.216.121.160]) by postgresql.org (Postfix) with ESMTP id 0F4F12E3386 for ; Thu, 29 Nov 2007 16:22:20 -0400 (AST) Received: from relay6.relay.sat.mlsrvr.com (localhost [127.0.0.1]) by relay6.relay.sat.mlsrvr.com (SMTP Server) with ESMTP id 1C6151B411C; Thu, 29 Nov 2007 15:22:19 -0500 (EST) Received: by relay6.relay.sat.mlsrvr.com (Authenticated sender: matthew-AT-zeut.net) with ESMTP id BA97F1B400D; Thu, 29 Nov 2007 15:22:18 -0500 (EST) Message-ID: <474F1FAE.3050700@zeut.net> Date: Thu, 29 Nov 2007 15:23:10 -0500 From: "Matthew T. O'Connor" User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: Matthew CC: pgsql-performance@postgresql.org Subject: Re: GiST indexing tuples References: <20071127183855.GA22330@uio.no> <245.1196264092@sss.pgh.pa.us> 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: 200711/384 X-Sequence-Number: 27799 Matthew wrote: > For instance, the normal B-tree index on (a, b) is able to answer queries > like "a = 5 AND b > 1" or "a > 5". An R-tree would be able to index these, > plus queries like "a > 5 AND b < 1". Sorry in advance if this is a stupid question, but how is this better than two index, one on "a" and one on "b"? I supposed there could be a space savings but beyond that?