Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 850AA64FD0D for ; Wed, 3 Sep 2008 23:06:41 -0300 (ADT) Received: from postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 15539-09 for ; Wed, 3 Sep 2008 23:06:38 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from outmail128092.authsmtp.net (outmail128092.authsmtp.net [62.13.128.92]) by postgresql.org (Postfix) with ESMTP id BBFC864FCF3 for ; Wed, 3 Sep 2008 23:06:38 -0300 (ADT) Received: from mail-c189.authsmtp.com (mail-c189.authsmtp.com [62.13.128.71]) by punt5.authsmtp.com (8.14.2/8.14.2/Kp) with ESMTP id m8426X1U057979; Thu, 4 Sep 2008 03:06:33 +0100 (BST) Received: from [192.168.0.2] (85-211-229-97.dyn.gotadsl.co.uk [85.211.229.97]) (authenticated bits=0) by mail.authsmtp.com (8.14.2/8.14.2/Kp) with ESMTP id m8426WSl026052; Thu, 4 Sep 2008 03:06:32 +0100 (BST) Subject: Re: hash index improving v3 From: Simon Riggs To: Xiao Meng Cc: pgsql-patches@postgresql.org, "Jonah H. Harris" In-Reply-To: References: Content-Type: text/plain Date: Thu, 04 Sep 2008 03:06:42 +0100 Message-Id: <1220494002.4371.813.camel@ebony.2ndQuadrant> Mime-Version: 1.0 X-Mailer: Evolution 2.12.0 Content-Transfer-Encoding: 7bit X-Server-Quench: 188b888e-7a26-11dd-bc7a-001f29070be2 X-AuthRoute: OCdxZQATClZOTQEd DAteCiNZVAwpPBRK HVkIKg5MJUcNSQVJ NksadRtFaAFbflxB HGQLW1xEUF97WWV/ aAkfZQBDYEtPQQdo WVZARU1QEQdtHhxP WxYaUB8VFFlGenhw YEQsX3VeXgp7fU4v SkZcQHABNGVmdWEe BBRFJVBTIR5Kfh4T aFl/U3NfNGdJBC9q VzwLFgwaHRhkHWxV SxoNZVMUTUsbVj85 XwoFAzQpEgUbHE0g X-Authentic-SMTP: 61633235383639.kestrel.dmpriest.net.uk:1186/Kp X-Report-SPAM: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-Virus-Status: No virus detected - but ensure you scan with your own anti-virus system! X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none X-Spam-Level: X-Archive-Number: 200809/35 X-Sequence-Number: 7050 On Mon, 2008-08-18 at 09:46 +0800, Xiao Meng wrote: > There's minor change against the previous > one( http://archives.postgresql.org/pgsql-hackers/2008-07/msg01183.php ). > * merge branch master(Aug 16) into the patch > * clean code and make some comment > Performance result is here > http://wiki.postgresql.org/wiki/Gsoc08-hashindex > > It seems hash index is a little better on index creation and > selection. > But maybe it's in the range of noise, I'm not sure. > I'd like to try it with a bigger dataset (e.g. table with 10GB) but > there is not enough space in my computer. > Anyone interest can make a test on a bigger data set. You don't give the text of the query used to do these performance tests, so I can't validate your test results. Right now it seems strange that the index is larger than a btree, yet the performance tests show that 3 times as much I/O was used accessing the btree. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support