Re: Optimizer refuses to hash join - Mailing list pgsql-performance

From Tom Lane
Subject Re: Optimizer refuses to hash join
Date
Msg-id 15403.1091120786@sss.pgh.pa.us
Whole thread Raw
In response to Optimizer refuses to hash join  (Stan Bielski <bielski@ece.cmu.edu>)
List pgsql-performance
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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