Re: Extremely irregular query performance - Mailing list pgsql-performance

From Bruce Momjian
Subject Re: Extremely irregular query performance
Date
Msg-id 200601140423.k0E4NX019385@candle.pha.pa.us
Whole thread Raw
In response to Re: Extremely irregular query performance  (Jean-Philippe Cote <jean-philippe.cote@crt.umontreal.ca>)
List pgsql-performance
Jean-Philippe Cote wrote:
>
>
> Can I actully know whether a given plan is excuted with GEQO on ?
> In other words, if I launch 'explain <query>', I'll get a given plan, but if I re-launch
> the <query> (withtout the 'explain' keyword), could I get a different
> plan given that GEQO induces some randomness ?
>
> >Is it the plan that is different in the fastest case with GEQO or is it
> >the time needed to plan that is causing the GEQO to beat the exhaustive
> >search?

Yes, is it likely that when using GEQO you would get a different plan
each time, so running it with and without EXPLAIN would produce
different plans.

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