Received: from localhost (unknown [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id 3E0AD9FCC77 for ; Fri, 26 Oct 2007 16:26:35 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-maia, port 10024) with ESMTP id 46207-05 for ; Fri, 26 Oct 2007 16:26:31 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 21FA79FCBE5 for ; Fri, 26 Oct 2007 16:26:30 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.1/8.14.1) with ESMTP id l9QJQQYP024985; Fri, 26 Oct 2007 15:26:26 -0400 (EDT) To: Jeff Davis cc: pgsql-docs@postgresql.org Subject: Re: Tsearch docs question In-reply-to: <1193423136.7624.56.camel@dogma.ljc.laika.com> References: <1193423136.7624.56.camel@dogma.ljc.laika.com> Comments: In-reply-to Jeff Davis message dated "Fri, 26 Oct 2007 11:25:36 -0700" Date: Fri, 26 Oct 2007 15:26:26 -0400 Message-ID: <24984.1193426786@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200710/102 X-Sequence-Number: 4523 Jeff Davis writes: > The Tsearch docs, under the GiST and GIN section, say: > "Lossiness [of GiST] causes serious performance degradation since random > access of heap records is slow and limits the usefulness of GiST > indexes." > The docs do go into some detail, but I think it causes some confusion, > also. Are you looking at CVS HEAD, or what was there in beta1? I rewrote that stuff a few days ago: http://developer.postgresql.org/pgdocs/postgres/textsearch-indexes.html > There's also a related issue: I think a RECHECK would be less costly if > you have the tsvectors materialized in the table (using triggers) and > index that. Maybe that could be a tip for using GiST indexes. Yeah, I mentioned that somewhere in the chapter, I think. regards, tom lane