mysql> describe user_message_state;
+--------------------+------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------------+------------------+------+-----+---------+-------+
| ums_user | int(10) unsigned | NO | PRI | NULL | |
| ums_thread | int(8) unsigned | NO | PRI | NULL | |
| ums_conversation | int(8) unsigned | NO | | 0 | |
| ums_read_timestamp | varbinary(14) | YES | | NULL | |
+--------------------+------------------+------+-----+---------+-------+
