One thing that sucks really bad with MyISAM is table level locking which can cause some serious issues at times when INSERT/UPDATE/DELETE load is very high. If you are experiencing problems in your application associated with locking, try converting your tables to InnoDB.
-ALTER TABLE table_name ENGINE = InnoDB;
and here’s another way:
– dump the table to a SQL file
– change table type from MyISAM to InnoDB in the dumped file
– disable keys (to speed up the process)
– SET AUTOCOMMIT to 0 (for speeding up the process)
– load the table
– SET AUTOCOMMIT to 1
– enable keys (the index is rebuilt at this point)
One is preferred over the other based on various factors such as time limit in which the conversion must be done.
these article is from : http://mysqldatabaseadministration.blogspot.com/2006/07/myisam-to-innodb.html