As spoted several times (see: msg26425 or https://groups.google.com/d/msg/tryton-dev/jrLyPxHMzeA/N6OdIf9y8tMJ) database support has multipe drawbacks:
- It adds complexity
- It slows Tryton,
- It is a wrong attempt for database management
- It prevents to do some great stuff with the framework like:
- Adding new field type with module
- Add new protocols on the fly
And since issue5384 is now implemented, the next step is to remove it on server side.