I wanted to configure my listener.ora to facilitate 2 Oracle SIDs both running on the same server. How do I do that ?
At present when I am checking the status, I am getting 2 services :-

Services Summary...
MPLA has 1 service handler(s)
PLSExtProc has 1 service handler(s)

What is the second service handler and why is it used..It is not any of my Oracle SIDs.