Routing hint does not seam work

mysql> use mariadb_test

Database changed

mysql> create table a (id serial, str varchar(255) not null, primary key(id));

Query OK, 0 rows affected (0.06 sec)

mysql> insert into a(id) values(null);

Query OK, 1 row affected, 1 warning (0.00 sec)

mysql> select last_insert_id();

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

| last_insert_id() |

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

|                1 |

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

1 row in set (0.00 sec)

mysql>

mysql> set @a = concat(last_insert_id(), @@hostname);

Query OK, 0 rows affected (0.00 sec)

mysql>

mysql> insert into a values(null, @a);

Query OK, 1 row affected (0.00 sec)

mysql> select @a /* maxscale route to master */;

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

| @a                      |

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

| 0galera3.learning.local |

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

1 row in set (0.00 sec)

mysql> select @a; -- maxscale route to master;

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

| @a                      |

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

| 0galera3.learning.local |

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

1 row in set (0.00 sec)

mysql> select @a; -- maxscale route to master ;

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

| @a                      |

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

| 0galera3.test.local |

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

1 row in set (0.00 sec)

mysql> select @a; # maxscale route to master ;

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

| @a                      |

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

| 0galera3.test.local |

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

1 row in set (0.00 sec)

mysql> select * FROM a;

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

| id | str                     |

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

|  1 |                         |

|  4 | 1galera1.test.local |

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

2 rows in set (0.00 sec)

mysql> select *, @a from a; --maxscale route to master;

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

| id | str                     | @a                      |

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

|  1 |                         | 0galera3.test.local |

|  4 | 1galera1.test.local | 0galera3.test.local |

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

2 rows in set (0.00 sec)