Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 9EC4864FCF7 for ; Thu, 4 Sep 2008 23:19:13 -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 69119-04 for ; Thu, 4 Sep 2008 23:19:10 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 2D92864FCEF for ; Thu, 4 Sep 2008 23:19:09 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id m852J5fU012088; Thu, 4 Sep 2008 22:19:05 -0400 (EDT) To: "Alex Hunsaker" cc: "Zdenek Kotala" , "Xiao Meng" , pgsql-patches@postgresql.org, "Jonah H. Harris" Subject: Re: hash index improving v3 In-reply-to: <34d269d40809041851r3330198ej6ccd0ae53e4260f9@mail.gmail.com> References: <48BFDA8D.3080506@sun.com> <29987.1220560114@sss.pgh.pa.us> <7627.1220569888@sss.pgh.pa.us> <34d269d40809041742r6a0703dbgfbdd012f7f19de2e@mail.gmail.com> <10995.1220577198@sss.pgh.pa.us> <34d269d40809041851r3330198ej6ccd0ae53e4260f9@mail.gmail.com> Comments: In-reply-to "Alex Hunsaker" message dated "Thu, 04 Sep 2008 19:51:14 -0600" Date: Thu, 04 Sep 2008 22:19:05 -0400 Message-ID: <12087.1220581145@sss.pgh.pa.us> From: Tom Lane 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: 200809/50 X-Sequence-Number: 7065 "Alex Hunsaker" writes: > On Thu, Sep 4, 2008 at 7:13 PM, Tom Lane wrote: >> * check that the queries actually use the indexes (not sure that the >> proposed switch settings ensure this, not to mention you didn't create >> the indexes) > Well I was assuming I could just test the speed of a hash join... Uh, no, hash joins have nearly zip to do with hash indexes. They rely on the same per-datatype support functions but that's the end of the commonality. regards, tom lane