Re: Improving GEQO

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: boix <boix(at)uclv(dot)cu>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Improving GEQO
Date: 2015-05-27 21:36:59
Message-ID: 3323.1432762619@sss.pgh.pa.us
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boix <boix(at)uclv(dot)cu> writes:
> Hello, my partner and me are working with the goal of improve the GEQO's
> performance, we tried with Ant Colony Optimization, but it does not
> improve, actually we are trying with a new variant of Genetic Algorithm,
> specifically Micro-GA. This algorithm finds a better solution than GEQO
> in less time, however the total query execution time is higher. The
> fitness is calculated by geqo_eval function. Does anybody know why this
> happens?

Well, for one thing, you can't just do this:

+ aux = aux1;

without totally confusing all your subsequent steps.

You'd want to copy the pointed-to data, likely, not the pointer.

regards, tom lane

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