Automatic Instance Registration

We have seen in the previous lesson how to set up the listener so it can reach other database nodes. This feature was used to set up connection load balancing and instance fail-over. This lesson explains the internal processes that Oracle has improved to handle these features.
A change to the PMON process, which is one of the background processes that runs for every database instance, has made these features possible. The PMON now automatically contacts the listener and tells it about database activity. It registers this information automatically with the listener. Prior to Oracle8i, only static information about the database instance (which you had to manually configure in the listener) was available to the listener. With this new PMON functionality, the listener receives automated dynamic instance information, including these items:

The automated instance registration feature of the PMON background process reduced the work required of you (the DBA) to describe each instance of a distributed or parallel system within the listener.ora configuration file.
The next lesson covers the new adapter called RADIUS.