Manual:$wgDBserver/hu

Details
Database host name or IP address. Found in.

If you are using MySQL on a non-standard port, you can use the "hostname:port" syntax, for example. Note that using a port number when you specify  as the host name will have no effect, as MySQL will connect through a socket instead. If the MySQL server is on the same server and you want to connect through a socket in a non-standard location, you can use the "localhost:socket" location, for example.

Tip: Use IP addresses where possible to avoid the overhead of a DNS lookup for every single connection to the wiki. will be faster than

is only for PostgreSQL configuration.

On Windows, having MySQL as the backend, some users report that using  for the server name instead of   increase the time to connect to the database a lot. So, in windows, it's recommended to use  instead of   if MySQL is on the same machine. See this forum thread.