Re: 8.4/9.0 simple query performance regression - Mailing list pgsql-performance

From Tom Lane
Subject Re: 8.4/9.0 simple query performance regression
Date
Msg-id 14955.1307401343@sss.pgh.pa.us
Whole thread Raw
In response to 8.4/9.0 simple query performance regression  (Josh Berkus <josh@agliodbs.com>)
List pgsql-performance
Josh Berkus <josh@agliodbs.com> writes:
> Just got this simple case off IRC today:
> [ hashed versus non-hashed subplan ]
> I'm at a bit of a loss as to what's happening here.

Possibly work_mem is smaller in the second installation?

(If I'm counting on my fingers right, you'd need a setting of at least a
couple MB to let it choose a hashed subplan for this case.)

            regards, tom lane

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