If you try to create or query a Federated table on an unreacheable network (could happen if you duplicate a database not located on the same private network for example), the query will not finish unless a timeout is reached (i am unsure on which one).

Doing a control+c while the query is running tries to kill the query, the query will be shown as a "Killed" command but wont finish and stays in "creating table" state until this timeout is reached, as a consequence, the CLI will still wait for the query to end and be unusable :

MariaDB [test]> CREATE TABLE t1 (   `id` int(20) NOT NULL   ) ENGINE="FEDERATED" DEFAULT CHARSET=latin1 CONNECTION='mysql://root@255.255.255.254:3306/db1/t1';

^CCtrl-C -- query killed. Continuing normally.

^CCtrl-C -- query killed. Continuing normally.

^CCtrl-C -- query killed. Continuing normally.

After some minutes the query will finally end and the CLI is usable again :

ERROR 1434 (HY000): Can't create federated table. Foreign data src error:  database: 'db1'  username: 'root'  hostname: '255.255.255.254'

ps: the problem might happen as well while not using the CLI but i only did try to access these unreacheable tables using CLI.