WARNING: Subscription for node down event still pending.
The warning messages are related to the Oracle TNS Listener's default subscription to the Oracle Notification Service (ONS). This subscription to ONS is introduced in Oracle 10g for RAC environment. Listener subscription to ONS is useful to use advanced features like Fast Application Notification events(FAN) , Fast Application Fail over (FAF) and Fast Connection Failover (FCN) in RAC. So in a non-RAC environment subscription to ONS is not needed. So in a standalone system we can disable it and thus avoid warning message.
