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Lesson 3Finding the listener service (Windows only)
ObjectiveView the current status of the listener service.

Finding Oracle listener Service

Under Windows, the Oracle Net Listener is implemented as a Windows Service. The following simulation will show you how to stop, start, and view the current status of this service. If you are running Unix, you should still do this simulation for the sake of general knowledge Finding Oracle Listener
If you have done a default Oracle install on NT, you should have a listener service named OracleOraHome11TNSListener, it should be started, and the startup mode should be automatic. Under Unix, to see the status of the listener, you would run listener control, and issue the status command.
Go ahead and look for the listener service on your system right now.

Listener Direct Hand-Off Information

The listener records direct hand-off events to dispatchers. These events are formatted into the following fields:
Timestamp * Presentation * Handoff * Error Code
Properties of direct hand-off fields are as follows:
  1. Each field is delimited by an asterisk (*).
  2. A successful connection or command returns a code of zero.
  3. A failure produces a code that maps to an error message.
Example: shows a direct hand-off event in the log file.

Example Listener Log Event for Direct Hand-Off

21-MAY-2012 10:54:55 * * handoff * 0

Listener Subscription for ONS Node Down Event Information

The listener subscribes to the Oracle Notification Service (ONS) node down event on startup if the ONS configuration file is available. This subscription enables the listener to remove the affected service when it receives node down event notification from ONS. The listener uses asynchronous subscription for the event notification. The following warning message is recorded to the listener log file on each STATUS command if the subscription has not completed, such as the ONS daemon is not running on the host.
WARNING: Subscription for node down event still pending and the listener cannot receive the ONS event while subscription is pending.
Other than that, no other listener functionality is affected.

Listener Oracle Clusterware Notification Information

If the required Oracle Clusterware (shown as CRS in the following log messages) libraries are installed and Oracle Clusterware is started on the host, then Oracle Listener will notify Oracle Clusterware about its status during start and stop processes. After successful notification, listeners record the event in the log and no message is recorded if the notification fails.

Listener completed notification to CRS on start
Listener completed notification to CRS on stop