Received: from localhost (unknown [200.46.204.183]) by developer.postgresql.org (Postfix) with ESMTP id 44C2F2E0050 for ; Thu, 10 Apr 2008 13:25:52 -0300 (ADT) Received: from developer.postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 60880-01 for ; Thu, 10 Apr 2008 13:25:46 -0300 (ADT) Received: from news.hub.org (news.hub.org [200.46.204.72]) by developer.postgresql.org (Postfix) with ESMTP id 5D9932E002C for ; Thu, 10 Apr 2008 13:25:46 -0300 (ADT) Received: from news.hub.org (news.hub.org [200.46.204.72]) by news.hub.org (8.14.1/8.14.1) with ESMTP id m3AGPjua064112 for ; Thu, 10 Apr 2008 13:25:45 -0300 (ADT) (envelope-from news@news.hub.org) Received: (from news@localhost) by news.hub.org (8.14.1/8.14.1/Submit) id m3AGI8Pv061231 for pgsql-performance@postgresql.org; Thu, 10 Apr 2008 13:18:08 -0300 (ADT) (envelope-from news) From: Gaetano Mendola X-Newsgroups: pgsql.performance Subject: Re: large tables and simple "= constant" queries using indexes Date: Thu, 10 Apr 2008 18:18:15 +0200 Organization: Hub.Org Networking Services Lines: 11 Message-ID: <47FE3DC7.4010700@gmail.com> References: <47FD2DF3.80500@gmail.com> <47FD3350.4060504@tweakers.net> <47FD4212.8040404@gmail.com> <47FDBE23.8020402@tweakers.net> <47FE27EB.8050804@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@news.hub.org To: John Beaver User-Agent: Thunderbird 2.0.0.12 (X11/20080227) In-Reply-To: <47FE27EB.8050804@gmail.com> To: pgsql-performance@postgresql.org 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: 200804/141 X-Sequence-Number: 29634 John Beaver wrote: > - Trying the same constant a second time gave an instantaneous result, > I'm guessing because of query/result caching. AFAIK no query/result caching is in place in postgres, what you are experiencing is OS disk/memory caching. Regards Gaetano Mendola