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Re: BUG #2930: Hash join abyssmal with many null fields. - Mailing list pgsql-bugs

From Tom Lane
Subject Re: BUG #2930: Hash join abyssmal with many null fields.
Date
Msg-id 18474.1169790592@sss.pgh.pa.us
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In response to BUG #2930: Hash join abyssmal with many null fields.  ("Maciej Babinski" <maciej+postgres@apathy.killer-robot.net>)
Responses Re: BUG #2930: Hash join abyssmal with many null fields.  (Maciej Babinski <maciej@killer-robot.net>)
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"Maciej Babinski" <maciej+postgres@apathy.killer-robot.net> writes:
> Hash join of columns with many null fields is very slow unless the null
> fields are commented out.

I see no bug here.  AFAICT your "much faster" query gets that way by
having eliminated all the candidate join rows on the B side.

            regards, tom lane

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