Re: Optimizer refuses to hash join

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От Tom Lane
Тема Re: Optimizer refuses to hash join
Дата
Msg-id 15403.1091120786@sss.pgh.pa.us
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Ответ на Optimizer refuses to hash join  (Stan Bielski <bielski@ece.cmu.edu>)
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Stan Bielski <bielski@ece.cmu.edu> writes:
> I having a great deal of difficulty getting postgres to do a hash join.
> Even if I disable nestloop and mergejoin in postgres.conf, the optimizer
> still refuses to select hash join.

Are you sure the join condition is hashjoinable?  You didn't say
anything about the datatypes involved ...

If it is, the other possibility is that you need to increase sort_mem
to accommodate the hash table.

            regards, tom lane

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