Re: I got bit by that darn GEQO setting again... - Mailing list pgsql-general

From David Helgason
Subject Re: I got bit by that darn GEQO setting again...
Date
Msg-id E01AEE43-48B6-11D8-BAA4-000A9566DA8A@uti.is
Whole thread Raw
In response to Re: I got bit by that darn GEQO setting again...  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
> Mike Mascari <mascarm@mascari.com> writes:
>> But just as a quick notice to those upgrading from 7.3 to 7.4 with
>> fully
>> normalized databases requiring > 11 joins, the GEQO setting can be a
>> killer...
>
> Uh ... dare I ask whether you think it's too high?  Or too low?

Just a data point: With a fresh 7.4 and

    geqo=on
    geqo_threshold=11
    geqo_generations=0
    geqo_effort=1
    geqo_pool_size=0
    geqo_selection_bias=2

a 12 table join was taking a whole second to plan until I manually
connected the tables (now it's in the order of a few ms).

I figure geqo had kicked in at that point.



d.


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