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Re: Problem with index and left join
Posted by: KimSeong Loh
Date: May 09, 2006 06:17PM

Using a TEXT as a join column?
This is a bad, TEXT can be upto 64KB and the comparison may need to compare upto 64KB, assuming character comparison is 1 operation per character, this is going to take lots of CPU time.

As in why the index is not used, I have no answer.
Maybe it will still su the index on some cases on the 4.1 not it may choose to sacn whole table depends to the value of each row.

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