Re: [HACKERS] Optimizer fails?

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От Bruce Momjian
Тема Re: [HACKERS] Optimizer fails?
Дата
Msg-id 199803250533.AAA26799@candle.pha.pa.us
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Ответ на Optimizer fails?  (Michal Mosiewicz <mimo@interdata.com.pl>)
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> Seq Scan on log  (cost=105832.15 size=699588 width=62)
>
> There is an index on log table, dt field. The index is b-tree.
> However it doesn't seem to be used. (Of course I have vacuumed it). The
> table has about 2M records. I don't think that Seq Scan is a good idea.
>
> Also, what if I agregate it on dt field to count(*) or sum some values.
> It would be sequentially scanned, then sorted, then grouped and finally
> agregated, right?

I assume you have vacuum analyze too?  It may help.

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