Listener won’t register database

I must admit, I’m a sqlnet hack.  I never really sat down to figure it out. If I have problems getting a database to register with a currently listener then I generally just add a separate listener. Well, today I was stuck on a system where I couldn’t add a second listener. Everything seems fine.  There was a default listener running on 1521 with  a database instance already registered. The first and second database were in the same ORACLE_HOME but I just couldn’t get the listener  to pick up the second databases.  I bounced and reloaded the listener and registered the second database

1. lsnrctl start

2. lsnrctl stop

3. lsnrctl start

4. alter system register

No dice. Then I tried

alter system set local_listener='(ADDRESS = (PROTOCOL=TCP)(HOST =myhost)(PORT=1521))’

and bang, it registered.

Of course, I guess I should track down why it wouldn’t register in the first place but getting it working for now was enough.