MariaDB> ANALYZE TABLE `mysql`.`db`;
+----------+---------+----------+-----------------------------+
| Table    | Op      | Msg_type | Msg_text                    |
+----------+---------+----------+-----------------------------+
| mysql.db | analyze | status   | Table is already up to date |
+----------+---------+----------+-----------------------------+
1 row in set (0.003 sec)

MariaDB> REPAIR TABLE `mysql`.`db`;
+----------+--------+----------+------------------------------------+
| Table    | Op     | Msg_type | Msg_text                           |
+----------+--------+----------+------------------------------------+
| mysql.db | repair | info     | Wrong CRC on datapage at 1         |
| mysql.db | repair | warning  | Number of rows changed from 3 to 0 |
| mysql.db | repair | status   | OK                                 |
+----------+--------+----------+------------------------------------+
3 rows in set (0.007 sec)

MariaDB> SELECT * FROM `mysql`.`db`;
Empty set (0.001 sec)

Mais dans ce cas d'erreur sur la table "db" de la base "'mysql", lors de la correction il a supprimé les données existantes que j'ai du recréer avec GRANT.