Not a cool new feature for Master_Host

I was surprised to find on a customer MySQL server this new syntax for Master_host in SHOW SLAVE STATUS.

*************************** 1. row ***************************
               Slave_IO_State: Connecting to master
                  Master_Host: or 10.XXX.XX.XXX
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: db1-354215-bin-log.000005
          Read_Master_Log_Pos: 1624
               Relay_Log_File: db2-354214-relay-log.000001

Is this a fancy new Percona Server feature? No. It’s operator error.

We read a little further to find.

             Slave_IO_Running: Connecting

                Last_IO_Errno: 2005
                Last_IO_Error: error connecting to master 'repl@ or 10.XXX.XX.XXX' - retry-time: 60  retries: 86400

How can this be created.
Using MySQL MHA, you get the following message in the output of commands to manage replication.

Thu Jan  3 17:06:40 2013 - [info]  All other slaves should start replication from here.
Statement should be: CHANGE MASTER TO MASTER_HOST=' or 10.XXX.XX.XXX', MASTER_PORT=3306,
 MASTER_LOG_FILE='db1-354215-bin-log.000005', MASTER_LOG_POS=1624, MASTER_USER='repl',

Needless to say, this syntax was taken literately, and MySQL did not complain.

I would suggest here that while MySQL does not do any validation on the value of the MASTER_HOST value in the CHANGE MASTER TO command to ensure it is resolvable it should at least do some validation to ensure the value is either a DNS entry or an IPV4,IPV6 value, that is space ‘ ‘, is not a valid character in these situations.