On Tue, Aug 18, 2009 at 5:08 AM, Simon Kimber<si...@internetstuff.ltd.uk> wrote: > I have indexes on siteid, datestamp and msgtype. > > Queries such as the following are constantly appearing in the slow > queries log: > > SELECT * FROM enquiries WHERE siteid = 59255 AND msgtype = 0 ORDER BY > datestamp DESC LIMIT 5;
Read the explanation of ORDER BY optimization: http://dev.mysql.com/doc/refman/5.1/en/order-by-optimization.html As it explains, you aren't providing a key it can use. If you create a multi-column index on siteid, msgtype, and datestamp, that will probably fix it. - Perrin -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
