session in 3.0.3 not saving userdata

I've solved this problem. Problem was that my cookie was overriding database session. In config file if using database for session, this line cannot have value:

$config['sess_cookie_name'] = 'mydomain';

In order for session to work using database, that value has to be empty:

$config['sess_cookie_name'] = '';

If it is not empty, CI will default to cookies for your session. This does not mean you cannot use cookies. You just have to loaded them via helper and they will work just fine.