mysql> describe historical_thread;
+-----------------------+-----------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------------------+-----------------+------+-----+---------+-------+
| hthread_id | int(8) unsigned | NO | PRI | NULL | |
| hthread_revision | int(8) unsigned | NO | PRI | NULL | |
| hthread_contents | blob | NO | | NULL | |
| hthread_change_type | int(4) unsigned | NO | | NULL | |
| hthread_change_object | int(8) unsigned | YES | | NULL | |
+-----------------------+-----------------+------+-----+---------+-------+
