Hi there @wschwarz,
welcome to KNIME Community!
If I got you right you have problem establishing connection with database, haven’t you? If that is the case database size doesn’t play a role in it as far as I understand the process. (And 2 GBs is not huge for database in my opinion).
Is there anything specific about this database? You can also check your log file. Maybe there is more info. From within KNIME go View--> Open KNIME log. Prior to that you can set you log level to DEBUG. From within KNIME go File --> Preferences --> KNIME.
Br,
Ivan