Invalid extent ranges for short character columns

MariaDB [test]> create table t1 (a char(5))engine=columnstore;

Query OK, 0 rows affected (0.405 sec)

MariaDB [test]> insert into t1 values ('abc'), ('xyz');

Query OK, 2 rows affected (0.200 sec)

Records: 2  Duplicates: 0  Warnings: 0

MariaDB [test]> select * from t1;

+------+

| a    |

+------+

| abc  |

| xyz  |

+------+

2 rows in set (0.041 sec)

MariaDB [test]> select calshowpartitionsbyvalue('t1', 'a', 'aa', 'zz');

ERROR 1815 (HY000): Internal error: IDB-2040: No partition found for the given value range.

MariaDB [test]> select c.table_schema, c.table_name, c.column_name, e.min_value, e.max_value from information_schema.columnstore_extents e, information_schema.columnstore_columns c where c.table_schema='test' and c.table_name='t1' and c.column_name='a' and c.object_id=e.object_id;

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

| table_schema | table_name | column_name | min_value | max_value |

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

| test         | t1         | a           |      NULL |      NULL |

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

1 row in set (0.029 sec)

MariaDB [test]> select calshowpartitionsbyvalue('t1', 'a', 'aa', 'zz');

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

| calshowpartitionsbyvalue('t1', 'a', 'aa', 'zz')                                                                                                              |

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

| Part#     Min                           Max                           Status

  0.0.1     abc                           xyz                           Enabled |

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

1 row in set (0.001 sec)

MariaDB [test]> select c.table_schema, c.table_name, c.column_name, e.min_value, e.max_value from information_schema.columnstore_extents e, information_schema.columnstore_columns c where c.table_schema='test' and c.table_name='t1' and c.column_name='a' and c.object_id=e.object_id;

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

| table_schema | table_name | column_name | min_value | max_value |

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

| test         | t1         | a           |   6513249 |   8026488 |

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

1 row in set (0.031 sec)