Userstat does not work for range queries on a partitioned table

--source include/have_partition.inc

SET @userstat.save= @@userstat;

set global userstat= 1;

create or replace table t (a int, key(a)) engine=MyISAM partition by hash(a) partitions 3;

insert into t values (1),(2),(3),(4),(5);

flush index_statistics;

flush table_statistics;

select * from t where a in (1,3);

show index_statistics;

show table_statistics;

explain select * from t where a in (1,3);

alter table t remove partitioning;

flush index_statistics;

flush table_statistics;

select * from t where a in (1,3);

show index_statistics;

show table_statistics;

explain select * from t where a in (1,3);

# Cleanup

drop table t;

set global userstat= @userstat.save;

MariaDB [test]> show index_statistics;

Empty set (0.000 sec)

MariaDB [test]> show table_statistics;

Empty set (0.000 sec)

MariaDB [test]> explain select * from t where a in (1,3);

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

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

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

|    1 | SIMPLE      | t     | range | a             | a    | 5       | NULL | 3    | Using where; Using index |

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

MariaDB [test]> show index_statistics;

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

| Table_schema | Table_name | Index_name | Rows_read | Queries |

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

| test         | t          | a          |         2 |       1 |

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

1 row in set (0.001 sec)

MariaDB [test]> show table_statistics;

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

| Table_schema | Table_name | Rows_read | Rows_changed | Rows_changed_x_#indexes |

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

| test         | t          |         2 |            0 |                       0 |

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

1 row in set (0.001 sec)

MariaDB [test]> explain select * from t where a in (1,3);

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

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

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

|    1 | SIMPLE      | t     | range | a             | a    | 5       | NULL | 2    | Using where; Using index |

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

1 row in set (0.001 sec)