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 75EC59DCA28 for ; Thu, 9 Mar 2006 08:04:32 -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 49034-02 for ; Thu, 9 Mar 2006 08:04:34 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from peufeu.com (boutiquenumerique.com [82.67.9.10]) by postgresql.org (Postfix) with ESMTP id AFE1F9DCA0B for ; Thu, 9 Mar 2006 08:04:29 -0400 (AST) Received: (qmail 31599 invoked from network); 9 Mar 2006 13:05:08 +0100 Received: from boutiquenumerique.com (HELO apollo13) (82.67.9.10) by boutiquenumerique.com with SMTP; 9 Mar 2006 13:05:08 +0100 Date: Thu, 09 Mar 2006 13:05:07 +0100 To: "Carlos Henrique Reimer" , "Andre Felipe Machado" , pgsql-performance@postgresql.org Subject: Re: firebird X postgresql 8.1.2 windows, performance comparison References: <20060309104131.27381.qmail@web53209.mail.yahoo.com> From: PFC Content-Type: text/plain; format=flowed; delsp=yes; charset=utf-8 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID: In-Reply-To: <20060309104131.27381.qmail@web53209.mail.yahoo.com> User-Agent: Opera M2/8.51 (Linux, build 1462) X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.104 required=5 tests=[AWL=0.104] X-Spam-Score: 0.104 X-Spam-Level: X-Archive-Number: 200603/96 X-Sequence-Number: 17533 > I hope tomorrow execute explain with the bitmapscan and seqscan enabled. > bitmapscans are almost always faster? Like all the rest, they're just a tool, which works great when used in its intended purpose : - Fetching just a few percent of the rows from a table is better served by an index scan - Fetching a lot of rows (>30-50%) from a table is better served by a seq scan - Bitmap scan comes in between and it's a very welcome addition. Also Bitmap scan will save your life if you have complex searches, like if you run a dating site and have an index on blondes and an index on boob size, because it can use several indexes in complex AND/OR queries. Common wisdom says simpler databases can be faster than postgres on simple queries. Reality check with pg 8.1 driven by PHP : - SELECT 1 mysql 5 ~ 42 us postgres ~ 70 us - SELECT * FROM users WHERE id=1 mysql 5 ~ 180 us postgres ~ 160 us Of course people doing stupid things, like using the database to keep a hit counter on their website which is updated on every hit, will say that postgres is slow.