Currently, catalog just log some cert's events in the two type method:
1.Log the change in the ship_to_rh info and Large_Agree with comment.
2.Log review action in the cert_rpm_event(check package,process testplan):

mysql> select distinct(activity) from  cert_rpm_event;
+----------------------+
| activity             |
+----------------------+
| addtestplan          | 
| change-content       | 
| Frozen               | 
| generatetestplan     | 
| Melted               | 
| required_32bits      | 
| required_64bits      | 
| bits32               | 
| bits64               | 
| addnewtestplanitem   | 
| check                | 
| uncheck              | 
| result_64bits        | 
| name                 | 
| result_32bits        | 
+----------------------+
15 rows in set (0.30 sec)

===============================================================================

mysql> desc cert_rpm_event;
+----------+---------------+------+-----+-------------------+----------------+
| Field    | Type          | Null | Key | Default           | Extra          |
+----------+---------------+------+-----+-------------------+----------------+
| id       | mediumint(9)  | NO   | PRI | NULL              | auto_increment | 
| rpm_id   | mediumint(9)  | YES  | MUL | NULL              |                | 
| mod_time | timestamp     | NO   |     | CURRENT_TIMESTAMP |                | 
| comment  | text          | YES  |     | NULL              |                | 
| activity | varchar(1000) | YES  |     | NULL              |                | 
| cert_id  | mediumint(9)  | YES  | MUL | NULL              |                | 
| modifier | mediumint(9)  | YES  |     | NULL              |                | 
+----------+---------------+------+-----+-------------------+----------------+
7 rows in set (0.00 sec)


We should revisit this above table and try to use "cert_log_event" table to log all cert's event.