Extension:LiquidThreads/historical thread table

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    |       |
+-----------------------+-----------------+------+-----+---------+-------+