Has Query optimizer improved in 5.4/5.5?

[mos]

I am using MySQL 5.1.30 (MyISAM) and the query optimizer is quite bad at 
choosing the proper index.

I often have to force it to use the correct index for Select statements, 
otherwise takes 50x to 100x slower than it should be.
Has the query optiimizer improved any for  later MySQL versions?
TIA
Mike


--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe:    http://lists.mysql.com/mysql?unsub=arch...@jab.org