Re: GEQO status? - Mailing list pgsql-hackers

From Ed Loehr
Subject Re: GEQO status?
Date
Msg-id 3A43FA27.603534A2@austin.rr.com
Whole thread Raw
In response to Re: GEQO status?  (Peter Eisentraut <peter_e@gmx.net>)
Responses Re: GEQO status?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> 
> The choices made by GEQO are intentionally random, so I would expect
> variation in tuple output order even for repetitions of the identical
> query.  If you got a semantically different result, that would indeed
> be a bug.  But it would most likely be a bug in the core planner, since
> GEQO has essentially no influence over whether the produced plan is
> correct or not.  GEQO merely forces specific choices of join order.
> All else is in the core planner.

You can remove the randomness by setting the Seed configuration value, if
the docs are correct.

Regards,
Ed Loehr


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