From: | Tino Schwarze <postgresql(at)tisc(dot)de> |
---|---|
To: | pgsql-admin(at)postgresql(dot)org |
Subject: | Re: performance on selecting a row in large tables |
Date: | 2008-02-04 21:20:50 |
Message-ID: | 20080204212050.GA17045@easy2.in-chemnitz.de |
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Thread: | |
Lists: | 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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