Unable to create a DOUBLE_PREC_HB histogram?

./mysql-test-run --start-and-exit

mysql -uroot -A --socket=/data0/psergey/dev2/maria-10.0-mwl253/mysql-test/var/tmp/mysqld.1.sock

MariaDB [(none)]> set histogram_size=10;

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> set histogram_type='double_prec_hb';

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> show variables like 'histogram%';

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

| Variable_name  | Value          |

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

| histogram_size | 10             |

| histogram_type | DOUBLE_PREC_HB |

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

2 rows in set (0.00 sec)

MariaDB [(none)]> use test;

Database changed

MariaDB [test]> create table t21 ( a int);

Query OK, 0 rows affected (0.01 sec)

MariaDB [test]> insert into t21 values (1),(2),(3),(4),(5);

Query OK, 5 rows affected (0.01 sec)

Records: 5  Duplicates: 0  Warnings: 0

MariaDB [test]> analyze table t21 persistent for all;

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

| Table    | Op      | Msg_type | Msg_text |

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

| test.t21 | analyze | status   | OK       |

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

1 row in set (0.00 sec)

MariaDB [test]> select *, hex(histogram),length(histogram) from mysql.column_stats where db_name='test' and table_name='t21'\G

*************************** 1. row ***************************

          db_name: test

       table_name: t21

      column_name: a

        min_value: 1

        max_value: 5

      nulls_ratio: 0.0000

       avg_length: 4.0000

    avg_frequency: 1.0000

        hist_size: 10

        hist_type: SINGLE_PREC_HB

        histogram:   �?�����

   hex(histogram): 0000FF3FFF7FFFBFFFFF

length(histogram): 10

1 row in set (0.00 sec)