GEQO: ERX

From: Tobias Zahn <tobias-zahn(at)arcor(dot)de>
To: pgsql-hackers(at)postgresql(dot)org
Subject: GEQO: ERX
Date: 2009-04-20 19:59:25
Message-ID: 49ECD41D.3000009@arcor.de
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Hello,
I was digging through the optimizer code and have a question regarding
the edge recombination crossover (ERX) of the GEQO. It might be
completely stupid and therefore I apologize for this in advance.

As far as I understand it, the idea of the ERX is the minimization of
edge failures. When reading in geqo_main.c and geqo_erx.c, it seams that
every iterative round (generation) it is checked by gimme_tour() if
there where any edge failures. When I understand the algorithm right,
there should be no edge failures.
Therefore I think about NOT checking for edge failures anymore, to save
some time. (If it just to make sure, it could be done only once in the
end.) Might that work or do I have some errors in my thoughts?

Thanks in advance,
Tobias

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