Hy.
I,ve installed some XOOPS sites by now without peoblems, but 1 hoster have the following case:
They told me
Connection to MySQL: You can only connect by socket to the MySQL instance.
And than explained to me what to set for phpmyadmin.

PHPMyAdmin configuration:
$cfg['Servers'][$i]['host'] = 'localhost';
$cfg['Servers'][$i]['port'] = '';
$cfg['Servers'][$i]['socket'] = '/data/web/clientname/var/lib/mysql/mysql.sock';
$cfg['Servers'][$i]['connect_type'] = 'socket';
$cfg['Servers'][$i]['extension'] = 'mysql';
Most common problem is a wrong path to the socket. Do not connect via tcp port 3306, this will not
work. You need to use your own socket, which is
/data/web/clientname/var/lib/mysql/mysql.sock .Use MySQL with options –p –u root, you
don’t need a password

Anyway, I did created with this installed phpmyadmin a database "test"

My problem is that in instalation procces I don't know what user / pass to set for database.
dbname -> test
dbuser -> root or something???
dbpass -> nothing or what?

How to tell XOOPS that MySQL use here custom socket? maybe it doesn't connect because XOOPS try to use default socket?

I can't figure out.
Anybody can help me with this?

I've got it.
For this kind of MySQL socket, on the install process, put localhost:path/to/custom/mysql/socket
Worked for me.