X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 984BC9DC98F for ; Fri, 20 Jan 2006 20:05:16 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 10243-07 for ; Fri, 20 Jan 2006 20:05:17 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from cassarossa.samfundet.no (cassarossa.samfundet.no [129.241.93.19]) by postgresql.org (Postfix) with ESMTP id BB05D9DC83F for ; Fri, 20 Jan 2006 20:05:12 -0400 (AST) Received: from trofast.ipv6.sesse.net ([2001:700:300:dc03:20e:cff:fe36:a766] helo=trofast.sesse.net) by cassarossa.samfundet.no with esmtp (Exim 4.50) id 1F06Fm-00045f-Al for pgsql-performance@postgresql.org; Sat, 21 Jan 2006 01:05:15 +0100 Received: from sesse by trofast.sesse.net with local (Exim 3.36 #1 (Debian)) id 1F06Fr-0007pz-00 for ; Sat, 21 Jan 2006 01:05:19 +0100 Date: Sat, 21 Jan 2006 01:05:19 +0100 From: "Steinar H. Gunderson" To: pgsql-performance@postgresql.org Subject: Re: [GENERAL] Creation of tsearch2 index is very slow Message-ID: <20060121000519.GA29755@uio.no> Mail-Followup-To: pgsql-performance@postgresql.org References: <26153.1137784469@sss.pgh.pa.us> <20060120201036.GE31908@svana.org> <26583.1137788505@sss.pgh.pa.us> <20060120205132.GF31908@svana.org> <26958.1137791955@sss.pgh.pa.us> <20060120213754.GG31908@svana.org> <7.0.1.0.2.20060120174141.039b03e8@earthlink.net> <6111.1137797436@sss.pgh.pa.us> <20060120225751.GA27230@uio.no> <6532.1137801157@sss.pgh.pa.us> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <6532.1137801157@sss.pgh.pa.us> X-Operating-System: Linux 2.6.14.3 on a x86_64 X-Message-Flag: Outlook? --> http://www.mozilla.org/products/thunderbird/ User-Agent: Mutt/1.5.11 X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.072 required=5 tests=[AWL=0.072] X-Spam-Score: 0.072 X-Spam-Level: X-Archive-Number: 200601/380 X-Sequence-Number: 16858 On Fri, Jan 20, 2006 at 06:52:37PM -0500, Tom Lane wrote: > It's also worth considering that the entire approach is a heuristic, > really --- getting the furthest-apart pair of seeds doesn't guarantee > an optimal split as far as I can see. Maybe there's some totally > different way to do it. For those of us who don't know what tsearch2/gist is trying to accomplish here, could you provide some pointers? :-) During my mini-literature-search on Google, I've found various algorithms for locating clusters in high-dimensional metric spaces[1]; some of it might be useful, but I might just be misunderstanding what the real problem is. [1] http://ieeexplore.ieee.org/iel5/69/30435/01401892.pdf?arnumber=1401892 , for instance /* Steinar */ -- Homepage: http://www.sesse.net/