I feel terrible. I thought I had sent out a notice about this, but I can’t find it anywhere, so here it is, better late than never.
José Vicente Nunez Zuleta has written a true JDBC poller for OpenNMS. Currently, OpenNMS just does a TCP port check on well known database ports. This is still the default, since true database polling requires a username and password, and since the chance of this being available out of the box is slim, we will continue to check ports.
However, once possible databases are discovered, they can be configured to allow OpenNMS to poll them using a true synthetic transaction. The poller will connect and attempt to get the database catalog. If this is successful, the poll is sucessful – otherwise it fails.