The database structures are generated by the modules. The storage engine generally default but is specified for a few tables based on the ACID requirement of the table.
| table | Preferred Engine |
|---|---|
| _messages | myISAM |
| _mail | myISAM |
| _egrades | InnoDB |
| _cgrades | InnoDB |
| _delinquency | InnoDB |
MyISAM OR InnoDB
| Required full text Search | myISAM |
| Require Transactions | innoDB |
| frequent select queries | myISAM |
| frequent insert,update,delete | innoDB |
| Row Locking (multi processing on single table) | innoDB |
| Relational base design | innoDB |
http://developer99.blogspot.com/2011/07/mysql-innodb-vs-myisam.html