>>>>> "Pete" == Pete Harlan <[EMAIL PROTECTED]> writes:
Pete> Hi,
Pete> So you're saying that there's no solution, no combination of indexes
Pete> that can help with 'where a=b or c=d'?
Not with MySQL (and not with any other SQL server I have tried, even
if I am sure that some of the bigger one MUST have something for this)
The current optimizer is completely general and can find key with many
parts from any possible where.
Adding detection of the above (in the general case) would make
everything a magnitude harder; As we have never needed this as TCX, I
haven't spent that much time trying to solve this :)
We have leaved this optimization until we have fixed other things we
find more important :)
Pete> We rewrote our program to eliminate these queries, solving our
Pete> immediate problem, but it seems like a surprising weakness for an
Pete> otherwise demonically fast dbms server.
Yes, I agree, but I think MySQL isn't alone in this case :)
Pete> To be fair to you, queries of that form are rare, in my experience.
Pete> Thanks for the help,
Regards,
Monty
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