I was fixing MySQL replication on a slave this past week. Everything seemed to be ready to go after bringing data over from the master manually. I went to connect the slave to the master and nothing happened. Whaaaaaa?
Last_IO_Errno: 1045 Last_IO_Error: error connecting to master 'firstname.lastname@example.org:3306' - retry-time: 60 retries: 86400
Let me look up MySQL error code 1045:
Error: 1045 SQLSTATE: 28000 (ER_ACCESS_DENIED_ERROR) Message: Access denied for user '%s'@'%s' (using password: %s)
That's not helpful. After some additional testing I realized the password might be too long. Sure enough, the CHANGE MASTER TO syntax guide states MASTER_PASSWORD has a maximum length of 32 characters (despite the MySQL client having a longer limit).
It's annoying that this limit exists and the