Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WAIYA-0007zh-1W for pgsql-hackers@arkaria.postgresql.org; Mon, 03 Feb 2014 12:22:54 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1WAIY9-0005IE-DD for pgsql-hackers@arkaria.postgresql.org; Mon, 03 Feb 2014 12:22:53 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WAIY8-0005I5-AI for pgsql-hackers@postgresql.org; Mon, 03 Feb 2014 12:22:52 +0000 Received: from mail.gransy.com ([2001:1528:137::f1]) by magus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WAIY1-0005qz-6b for pgsql-hackers@postgresql.org; Mon, 03 Feb 2014 12:22:51 +0000 Received: from antispam.gransy.com (antispam.gransy.com [77.78.104.124]) by mail.gransy.com (Postfix) with ESMTP id 47E1D508D1A for ; Mon, 3 Feb 2014 13:22:44 +0100 (CET) X-Virus-Scanned: G-Hosting.cz + Station.cz + Klenot.cz + Subreg.cz amavisd-new at antispam.gransy.com Received: from mail.gransy.com ([82.208.29.194]) by antispam.gransy.com (antispam.gransy.com [77.78.104.124]) (amavisd-new, port 10024) with ESMTP id HA8GSgZ8kBkV for ; Mon, 3 Feb 2014 13:22:51 +0100 (CET) Received: from sq.gransy.com (elizabeth.gransy.com [89.187.132.199]) (Authenticated sender: tv@fuzzy.cz) by mail.gransy.com (Postfix) with ESMTPA id 79639508C69; Mon, 3 Feb 2014 13:22:42 +0100 (CET) Received: from 212.47.19.46 (SquirrelMail authenticated user tv@fuzzy.cz) by sq.gransy.com with HTTP; Mon, 3 Feb 2014 13:22:41 +0100 Message-ID: In-Reply-To: References: <51D00FB6.9030008@vmware.com> <528533D9.3040501@vmware.com> <52E141BA.5000302@vmware.com> <52E4141E.60609@fuzzy.cz> <52E42AD0.5060600@vmware.com> <52E4AA3A.9000607@fuzzy.cz> <52E53458.2010106@vmware.com> <52E72A10.5040908@fuzzy.cz> <52EE21D1.2080804@vmware.com> <52EED0FC.2060503@fuzzy.cz> <52EEF472.9020106@fuzzy.cz> Date: Mon, 3 Feb 2014 13:22:41 +0100 Subject: Re: GIN improvements part2: fast scan From: "Tomas Vondra" To: obartunov@gmail.com Cc: "Tomas Vondra" , "Pgsql Hackers" User-Agent: SquirrelMail/1.4.22 MIME-Version: 1.0 Content-Type: text/plain;charset=utf-8 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-Pg-Spam-Score: -1.9 (-) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-hackers Precedence: bulk Sender: pgsql-hackers-owner@postgresql.org Hi Oleg, On 3 Únor 2014, 7:53, Oleg Bartunov wrote: > Tomasa, it'd be nice if you use real data in your testing. I'm using a mailing list archive (the benchmark is essentially a simple search engine on top of the archive, implemented using built-in full-text). So I think this is a quite 'real' dataset, not something synthetic. The queries are generated, of course, but I strived to make them as real as possible. Sure, this is not a hstore-centric benchmark, but the thread is about GIN indexes, so I think it's fair. > One very good application of gin fast-scan is dramatic performance > improvement of hstore/jsonb @> operator, see slides 57, 58 > http://www.sai.msu.su/~megera/postgres/talks/hstore-dublin-2013.pdf. > I'd like not to lost this benefit :) Yes, that's something we could/should test, probably. Sadly I don't have a dataset or a complete real-world test case at hand. Any ideas? I certainly agree that it'd be very sad to lose the performance gain for hstore/json. OTOH my fear is that to achieve that gain, we'll noticeably slow down other important use cases (e.g. full-text search), which is one of the reasons why I was doing the tests. regards Tomas -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers