Re: Prevent DISTINCT from using temporary tables
For performing a DISTINCT operation, MySQL first sorts the rows by the distinct column ('chromosome' in your case) for those rows matching the WHERE condition.
A simple way to avoid sorting would be to have an index on the two columns 'dataset_id','chromosome')
Shlomi
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August 25, 2008 09:07PM
Re: Prevent DISTINCT from using temporary tables
6687
August 30, 2008 11:42AM
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