Oracle apps upgrade db connection listener problem ORA-27101

Scenario : Upgraded the Database to 11.2.0.2 in an Oracle EBS environment.

Connection via sqlplus is working fine.

Manually configured the listener. Checked tnsping. Tnsping is working fine with the status as ok.

However when connecting to the Database for doing the other post activities, the failure occurs, and upon investigation, it has been found out that the actual connectivity via a tnsnames.ora is not occurring properly.

This has been verified by the following:

[devora@linux_server03 ~]$ sqlplus apps/apps@migr
SQL*Plus: Release 11.2.0.2.0 Production on Tue May 10 14:30:43 2011
Copyright (c) 1982, 2010, Oracle.  All rights reserved.
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
Linux-x86_64 Error: 2: No such file or directory
Process ID: 0
Session ID: 0 Serial number: 0

Enter user-name:


=======

To resolve it :-


SQL> ALTER SYSTEM SET LOCAL_LISTENER="(address=(protocol=TCP)(host=linux_server03) (port=1528))" SID='MIGR';
System altered.
SQL>

or

you can add the below entry in the init.ora file and save it..

 LOCAL_LISTENER=MIGR


=======

Always ensure that you start the listener and then only start the Database for Oracle EBS (non-rac) environment.