Re: performance on selecting a row in large tables
От | Tino Schwarze |
---|---|
Тема | Re: performance on selecting a row in large tables |
Дата | |
Msg-id | 20080204212050.GA17045@easy2.in-chemnitz.de обсуждение исходный текст |
Ответ на | performance on selecting a row in large tables ("Rainer Spittel" <rainer.spittel@terralink.co.nz>) |
Список | pgsql-admin |
Hi Rainer, On Tue, Feb 05, 2008 at 09:07:26AM +1300, Rainer Spittel wrote: > When performing a 'select col01_id from table limit 1 offset 100000;', As Tom already stated, the result of this query is a bit random since there is no ordering at all. What are you actually querying for? Try tuning queries before tuning the server. > Looking forward for any comments or suggestions. Here it is, right at the bottom of your mail: > ---------------------------(end of broadcast)--------------------------- > TIP 6: explain analyze is your friend explain analyze select col01_id from table limit 1 offset 100000; will run the query and show you how the query plan looks and how much time is spent. It is likely to say "SeqScan" somewhere - a sequential scan of the tabe. HTH! Tino. -- www.craniosacralzentrum.de www.spiritualdesign-chemnitz.de Tino Schwarze * Lortzingstraße 21 * 09119 Chemnitz
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