Re: Problem (bug?) with like

> I am thinking that the rules for selectivity of LIKE patterns probably
> need to be modified.  Presently the code assumes that a long constant
> string has probability of occurrence proportional to the product of the
> probabilities of the individual letters.  That might be true in a random
> world, but people don't search for random strings.  I think we need to
> back off the selectivity estimate by some large factor to account for
> the fact that the pattern being searched for is probably not random.
> Anyone have ideas how to do that?

But what about '%A%' vs. '%AC%'.  Seems the second is reasonably
different from the first the our optimizer may be fine with that.  Is it
only when the strings get longer that we lose specificity?

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