Hi David,
There is already a bug opened for this issue. [URL]MySQL Bugs: #55288: Use of the underscore or hyphen for variables and options is confusing
There should some specific documentation for that OR they should keep any one out of “_” and “-” but as still it’s in feature requests for Oracle, we can’t do anything for that.
But I would suggest its better to use _ rather then -. Because you can use _ everywhere, including my.cnf and command line . But - is not working with SET like
mysql> SET global default_storage_engine = InnoDB;
Query OK, 0 rows affected (0.01 sec)
mysql> SET global default-storage-engine = InnoDB;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘-storage-engine = InnoDB’ at line 1
mysql>
You can use _ with server variables too. Check here comment by “[1 Nov 2008 20:16] Sveta Smirnova” [URL]MySQL Bugs: #40368: mysqld_safe not honouring underscore same as dash on server options