Re: RES: RES: Improving select peformance

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От Tom Lane
Тема Re: RES: RES: Improving select peformance
Дата
Msg-id 28235.1186107181@sss.pgh.pa.us
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Ответ на RES: RES: Improving select peformance  ("Carlos H. Reimer" <carlos.reimer@opendb.com.br>)
Ответы RES: RES: RES: Improving select peformance  ("Carlos H. Reimer" <carlos.reimer@opendb.com.br>)
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"Carlos H. Reimer" <carlos.reimer@opendb.com.br> writes:
> In this case, I believe the best choice to improve the performance of this
> particular SQL statement is adding the 'set join_collapse_limit = 1;' just
> before the join statement, correct?

That's a mighty blunt instrument.  The real problem with your query is
the misestimation of the join sizes --- are you sure the table
statistics are up to date?  Maybe you'd get better estimates with more
statistics (ie, increase the stats target for these tables).

            regards, tom lane

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