Memory tables use hash indexes by default instead of b-tree. Try changing the index, that should help significantly.
regards, Walter On Tue, Mar 31, 2009 at 6:47 PM, mos <mo...@fastmail.fm> wrote: > I'm using MySQL 5.1.30 and have several memory tables with indexes on the > appropriate columns. When I try and join 2 particular memory tables together > to get 5k rows, it takes 90 seconds. > This is incredibly slow considering table1 has 11k rows and table2 has 5k > rows. A table join like this should take 10 ms. > > An explain shows it is not using and index for the table but Extra has > "Using where;Using join buffer". I can try and use "Force Index(..)" and it > still will not use the index. > > If I use the MyISAM table instead of that one particular memory table the > query takes 800ms which is reasonably fast. > > Is there a way to force it not to use the join buffer? > Has anyone else noticed the slow memory table joins in 5.1? > > TIA > Mike > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/mysql?unsub=li...@olindata.com > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
