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Re: What index to use for "where col is IS NOT NULL" query
Posted by: Øystein Grøvlen
Date: October 25, 2013 12:29AM

Hi,

The only possible index is an index on the R_TIMEOUT column. Not sure how much it will help you, though. For the given query, unless more than 80-90% of column values are null, a full table scan will normally be quicker than going through an index to find relevant records.

Øystein Grøvlen,
Senior Principal Software Engineer,
MySQL Group, Oracle,
Trondheim, Norway

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