Symptoms of the Problem
In the listener log file you constantly get the following warning message.
WARNING: Subscription for node down event still pending
If you have oracle database greater than 10g or newer version or 11g then in the listener log file you get the warning message.
Cause of the Problem
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.
Solution of the Problem
Disable subscription for listener to ONS. This can be done by setting the following parameter in the listener.ora.
SUBSCRIBE_FOR_NODE_DOWN_EVENT_{listener_name}=OFF
Where {listener_name} should be replaced with the actual listener name configured in the LISTENER.ORA file.
Suppose your have default listener name and it is LISTENER. Then in the listener.ora file(by default in location $ORACLE_HOME/network/admin on unix) add the following entry in a new line,
SUBSCRIBE_FOR_NODE_DOWN_EVENT_LISTENER=OFF
After that you need to stop and start the listener by,
lsnrctl stop
lsnrctl start
Alternatively you can reload the listener if availability is important to you. Do it just by,
lsnrctl reload
This will prevent the messages from being written to the log file.
This changes also prevent the TNS listener hanging intermittently which will be discussed in another topic.
Note that, setting the above parameter OFF in listener.ora disables a necessary RAC functionality.
No comments:
Post a Comment