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Re: MySQL 5.5 Query Optimizer - Massive Regression (vs 5.0)
Posted by: Chris Ricks
Date: February 02, 2012 03:06AM

It looks like the problem is actually quite simple.

For some incredibly strange reason, having an ORDER BY clause causes selection of the index that can be used to satisfy the ORDER BY without filesort as opposed to selection of the index that can actually return the results in a respectable amount of time.

No amount of playing with max_length_for_sort_data is helping this.

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Re: MySQL 5.5 Query Optimizer - Massive Regression (vs 5.0)
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February 02, 2012 03:06AM


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