On Apr 13, 2011, at 6:19 PM, Tomas Vondra <t...@fuzzy.cz> wrote:
> Yes, I've had some lectures on non-linear programming so I'm aware that
> this won't work if the cost function has multiple extremes (walleys /
> hills etc.) but I somehow suppose that's not the case of cost estimates.

I think that supposition might turn out to be incorrect, though.  Probably what 
will happen on simple queries is that a small change will make no difference, 
and a large enough change will cause a plan change.  On complex queries it will 
approach continuous variation but why shouldn't there be local minima?

...Robert
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