Re: patch for geqo tweaks - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: patch for geqo tweaks
Date
Msg-id 20151104182918.GS6104@alvherre.pgsql
Whole thread Raw
In response to Re: patch for geqo tweaks  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: patch for geqo tweaks  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:

> Having said that, though, I believe that it's also probably a
> *different* initial shuffle, which may well mean that GEQO gives
> different plans in some cases.  That doesn't bother me as long as
> we only make the change in HEAD, but does anyone want to complain?

Uh, do we promise that plans found by geqo are stable?  That would seem
odd to me -- wouldn't they change shape on a whim, say because the stats
are different?  It seems odd to look for plan stability using a genetic
algorithm.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services



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