Re: slow query performance

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От Dave Weaver
Тема Re: slow query performance
Дата
Msg-id 200310301005.h9UA5L400802@server-2.twdl.co.uk
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Ответ на slow query performance  ("Dave Weaver" <davew@wsieurope.com>)
Ответы Re: slow query performance
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Shridhar Daithankar wrote:

> Dave Weaver wrote:

> > A simple "SELECT count(*) from obs" query takes around that sort of time

> > too.

>

> That is no test. Postgresql will always fetch the entire table.

 

OK, I wasn't aware of that.

 

> > I have run "vacuumdb --analyze obs", to little effect.

>

> Check http://www.varlena.com/varlena/GeneralBits/Tidbits/perf.html for general

> tuning tips

 

Thanks for the link - I will read and digest.

 

> and do a vacuum full if table is updated frequently. Also reindex

> the indexes after vacuum. It will take quite some time though.

 

The version of Postgres that I'm running (7.1.3) doesn't seem to have a "vacuum full".

I have reindexed after a vacuum, with liitle-to-no effect.

 

Dave.

 

 

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