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No keys used tho fields have keys: why?
Posted by: Margaret MacDonald
Date: March 05, 2005 12:28PM

I have a LEFT JOIN query that consistently takes on the order of a second to execute on my dev machine regardless of how many records (in the range 3-200 from a table of 175K records) are returned.

EXPLAIN tells me that no keys are being used for the main branch of the join, even though indexes are defined on the columns being returned. A key (PRIMARY) is being used on the minor branch.

What would cause the engine not to use keys that are defined for use?

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No keys used tho fields have keys: why?
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