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Re: MyISAM, Select and MoveFirst
Posted by: Bob Field
Date: July 13, 2006 07:35AM

Anytime you use a LIKE operator where the pattern has an initial wildcard character, a full table scan must be performed to find all matching records. So no index would be of use even if one existed. The variable delay before returning the first record probably has to do with how many rows it had to scan before encounting that particular keyword. The indexes can help to find the matching rows in Table2. The EXPLAIN command can give you more detail on this. I suggest you look into using a FULLTEXT index to improve performance.

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