X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id B85709FA4EA for ; Wed, 10 May 2006 07:09:08 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 72905-06 for ; Wed, 10 May 2006 07:09:00 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from service-web.de (p15093784.pureserver.info [217.160.106.224]) by postgresql.org (Postfix) with ESMTP id 2D6E29FA4DE for ; Wed, 10 May 2006 07:09:00 -0300 (ADT) Received: from [10.100.1.50] (074-016-066-080.eggenet.de [80.66.16.74]) by service-web.de (Postfix) with ESMTP id 4078720002F; Wed, 10 May 2006 12:08:59 +0200 (CEST) Message-ID: <4461BB9E.5030607@wildenhain.de> Date: Wed, 10 May 2006 12:08:30 +0200 From: Tino Wildenhain User-Agent: Mozilla Thunderbird 1.0.6 (X11/20050929) X-Accept-Language: de-DE, de, en-us, en MIME-Version: 1.0 To: Thomas Vatter Cc: pgsql-performance@postgresql.org Subject: Re: in memory views References: <4461AFFF.7060200@network-inventory.de> <4461B3DE.6030700@wildenhain.de> <4461B899.4030502@network-inventory.de> In-Reply-To: <4461B899.4030502@network-inventory.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200605/234 X-Sequence-Number: 19021 Thomas Vatter schrieb: > Tino Wildenhain wrote: > >> Thomas Vatter schrieb: >> >>> is there a possibility for creating views or temp tables in memory to >>> avoid disk io when user makes select operations? >> >> >> >> No need. The data will be available in OS and database caches if >> they are really required often. If not, tune up the caches and >> do a regular "pre select". >> >> Regards >> Tino >> >> > > hmm, I am selecting a resultset with 1300 rows joined from 12 tables. > with jdbc I am waiting 40 seconds until the first row appears. The > following rows appear really fast but the 40 seconds are a problem. Well you will need the equally 40 seconds to fill your hypothetical in memory table. (even a bit more due to the creation of a datastructure). So you can do the aproaches of semi materialized views (that are in fact writing into a shadow table) or just prefetch your data at time - just at the times you would refill your memory tables if they existed. A cronjob with select/fetch should do. Regards Tino