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Re: Unexpected benchmark results due to query optimizer?
Posted by: Kees van den Broek
Date: September 07, 2005 06:47AM

In my original message, "dip" refers to a dip in a line in the graph, it's actually a "sudden speedup" which is caused by something unknown. I should have rephrased it. I don't think b-tree branching is the cause in this case.

In the meantime, I've read something about the order of indexes. It seems that the order of an index is not to be determined by the user. MySQL is able to figure out the best order by itself. MySQL will also traverse the index in the best order depending on the query. Even backwards when necessary.
That could be the cause, but I'm still not very sure about it.

I've looked into the MySQL source code for a little while, but it's not really self-explanatory to me.

I guess it's more complicated.

Thanks for you help.

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Re: Unexpected benchmark results due to query optimizer?
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