Re: Optimisation deficiency: currval('seq')-->seq scan, constant-->index scan

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От Bruce Momjian
Тема Re: Optimisation deficiency: currval('seq')-->seq scan, constant-->index scan
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Msg-id 200010140419.AAA22701@candle.pha.pa.us
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Ответ на Re: Optimisation deficiency: currval('seq')-->seq scan, constant-->index scan  (Tom Lane <tgl@sss.pgh.pa.us>)
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> Tiago Antão <tra@fct.unl.pt> writes:
> >   One thing it might be interesting (please tell me if you think
> > otherwise) would be to improve pg with better statistical information, by
> > using, for example, histograms.
> 
> Yes, that's been on the todo list for a while.
> 
> > There is a good article regarding this:
> > http://www.db2mag.com/summer00/programmer.shtml
> 
> Interesting article.  We do most of what she talks about, but we don't
> have anything like the ClusterRatio statistic.  We need it --- that was
> just being discussed a few days ago in another thread.  Do you have any
> reference on exactly how DB2 defines that stat?
> 

Added to TODO:
* Keep statistics about clustering of table rows

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