i forgot to wrote what happens after repair
mysql> REPAIR TABLE Attachments;
+-----------------+--------+----------+-----------------------------+
| Table | Op | Msg_type | Msg_text |
+-----------------+--------+----------+-----------------------------+
| rt3.Attachments | repair | status | Table is already up to date |
+-----------------+--------+----------+-----------------------------+
1 row in set, 1 warning (6 min 30.36 sec)