Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1YBxPT-0002Da-6I for pgsql-performance@arkaria.postgresql.org; Fri, 16 Jan 2015 03:17:19 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1YBxPS-0007UF-IY for pgsql-performance@arkaria.postgresql.org; Fri, 16 Jan 2015 03:17:18 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1YBxPR-0007U8-Bv for pgsql-performance@postgresql.org; Fri, 16 Jan 2015 03:17:17 +0000 Received: from mail.catalyst.net.nz ([2404:130:0:10::40:0]) by makus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1YBxPO-0002nl-Cw for pgsql-performance@postgresql.org; Fri, 16 Jan 2015 03:17:15 +0000 Received: from localhost (localhost [127.0.0.1]) by mail.catalyst.net.nz (Postfix) with ESMTP id 8573131BFC; Fri, 16 Jan 2015 16:17:13 +1300 (NZDT) X-Virus-Scanned: Debian amavisd-new at catalyst.net.nz Received: from mail.catalyst.net.nz ([127.0.0.1]) by localhost (bertrand.catalyst.net.nz [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8wh5Qwrx93or; Fri, 16 Jan 2015 16:17:12 +1300 (NZDT) Received: from [IPv6:2404:130:0:1000:9107:c07f:1300:5b09] (unknown [IPv6:2404:130:0:1000:9107:c07f:1300:5b09]) (Authenticated sender: mark.kirkwood) by mail.catalyst.net.nz (Postfix) with ESMTPSA id C388B31BEE; Fri, 16 Jan 2015 16:17:12 +1300 (NZDT) Message-ID: <54B882B8.2050303@catalyst.net.nz> Date: Fri, 16 Jan 2015 16:17:12 +1300 From: Mark Kirkwood User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Josh Berkus , postgres performance list Subject: Re: Strange choice of general index over partial index References: <54B83F70.7080004@agliodbs.com> <54B85D32.7090106@catalyst.net.nz> <54B87820.3090101@catalyst.net.nz> <54B88032.7020206@catalyst.net.nz> In-Reply-To: <54B88032.7020206@catalyst.net.nz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -1.9 (-) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org On 16/01/15 16:06, Mark Kirkwood wrote: > A bit more poking about shows that the major factor (which this fake > dataset anyway) is the default for effective_cache_size (changes from > 128MB to 4GB in 9.4). Increasing this makes 9.2 start using the > files_in_flight index in a plain index scan too. > Arrg - misread the planner output....in 9.2 what changes is a plan that uses an index scan on the *file_state* index (not files_in_flight)...which appears much faster than the bitmap scan on file_state. Apologies for the confusion. I'm thinking that I'm seeing the effect Tom has just mentioned. regards Mark -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance