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
Ответ на
performance on selecting a row in large tables (Rainer Spittel)
Список
Дерево обсуждения
Re: performance on selecting a row in large tables "Rainer Spittel" <rainer.spittel@terralink.co.nz>
Re: performance on selecting a row in large tables Tino Schwarze <postgresql@tisc.de>
Re: performance on selecting a row in large tables Tom Lane <tgl@sss.pgh.pa.us>
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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