LevelDB (and MyISAM): Wrong result (missing rows) with range access, prefix key on a char column

DROP TABLE IF EXISTS t1;

CREATE TABLE t1 (pk INT PRIMARY KEY, c CHAR(10), KEY(c(1))) ENGINE=LevelDB;

INSERT INTO t1 VALUES (40,'october'),(41,'february');

SELECT * FROM t1 WHERE c NOT IN ('l', 'f', 'w');

+----+---------+

| pk | c       |

+----+---------+

| 40 | october |

+----+---------+

+----+----------+

| pk | c        |

+----+----------+

| 41 | february |

| 40 | october  |

+----+----------+

+----+-------------+-------+-------+---------------+------+---------+------+------+----------+-------------+

| id | select_type | table | type  | possible_keys | key  | key_len | ref  | rows | filtered | Extra       |

+----+-------------+-------+-------+---------------+------+---------+------+------+----------+-------------+

|  1 | SIMPLE      | t1    | range | c             | c    | 2       | NULL |   30 |   100.00 | Using where |

+----+-------------+-------+-------+---------------+------+---------+------+------+----------+-------------+

revision-id: psergey@askmonty.org-20130319110939-z2fi30aslmhwxslk

revno: 4611

branch-nick: mysql-5.6-leveldb