3 Listener

You can use Enterprise Manager to manage Oracle Listener targets. From the Enterprise Manager Listener home page, you can monitor key metrics that can help determine the performance and availability of the listener and help you troubleshoot potential performance problems.

3.1 General Status

This metric is a container for a set of metrics that provide general information about the listener target.

3.1.1 Alias

The alias is an alternative name for the listener. On the Metric Detail page, you can see the value of this metric only when you select one of the Real Time refresh options. The alias also appears on the Listener home page.

3.1.1.1 Metric Summary

The following table shows how often the metric's value is collected.

Target Version	Collection Frequency
All Versions	Every 15 Minutes

3.1.1.2 Data Source

This metric is derived from the STATUS command of the Listener Control Utility. For more information, see the section on Listener Administration in the Oracle Net Services Administrator's Guide.

3.1.1.3 User Action

Not applicable.

3.1.2 Security

The value of this metric shows whether or not a password is required to run specific commands with the Listener Control Utility.

3.1.2.1 Metric Summary

The following table shows how often the metric's value is collected.

Target Version	Collection Frequency
All Versions	Every 15 Minutes

3.1.2.2 Data Source

This metric is derived from the STATUS command of the Listener Control Utility. For more information, see the section on Listener Administration in the Oracle Net Services Administrator's Guide.

3.1.2.3 User Action

Not applicable.

3.1.3 SID List

This metric lists the System Identifiers (SIDs) for the services monitored by the listener.

3.1.3.1 Metric Summary

The following table shows how often the metric's value is collected.

Target Version	Collection Frequency
All Versions	Every 15 Minutes

3.1.3.2 Data Source

The list of SIDs for the listener is stored in the listener.ora configuration file.

3.1.3.3 User Action

Not applicable.

3.1.4 SNMP Status

This metric indicates whether or not the listener can respond to queries from an SNMP-based network management system.

3.1.4.1 Metric Summary

The following table shows how often the metric's value is collected.

Target Version	Collection Frequency
All Versions	Every 15 Minutes

3.1.4.2 Data Source

This metric is derived from the STATUS command of the Listener Control Utility. For more information, see the section on Listener Administration in the Oracle Net Services Administrator's Guide.

3.1.4.3 User Action

Not applicable.

3.1.5 Start Date

This metric represents the day and time when the listener was last started. On the Metric Detail page, you can see the value of this metric only when you select one of the Real Time refresh options. This metric also appears on the Enterprise Manager Listener home page.

3.1.5.1 Metric Summary

The following table shows how often the metric's value is collected.

Target Version	Collection Frequency
All Versions	Every 15 Minutes

3.1.5.2 Data Source

This metric is derived from the STATUS command of the Listener Control Utility. For more information, see the section on Listener Administration in the Oracle Net Services Administrator's Guide.

3.1.5.3 User Action

Not applicable.

3.1.6 TNS Address

This metric displays the protocal, host, and port information for the listener. On the Metric Detail page, you can see the value of this metric only when you select one of the Real Time refresh options. The TNS address also appears on the Listener home page.

3.1.6.1 Metric Summary

The following table shows how often the metric's value is collected.

Target Version	Collection Frequency
All Versions	Every 15 Minutes

3.1.6.2 Data Source

The TNS address of the Listener is defined in the listener.ora configuration file. For more information, see the Oracle Net Services Administrator's Guide.

3.1.6.3 User Action

Not applicable.

3.1.7 Trace Level

This metric represents the level of tracing currently enabled for the listener. Tracing can be used to troubleshoot problems with the listener by saving additional information to the trace file. For more information about the trace levels you can set for the listener, see the information about the Listener Control Utility in the Oracle Net Services Reference Manual.

On the Metric Detail page, you can see the value of this metric only when you select one of the Real Time refresh options.

3.1.7.1 Metric Summary

The following table shows how often the metric's value is collected.

Target Version	Collection Frequency
All Versions	Every 15 Minutes

3.1.7.2 Data Source

This metric is derived from the STATUS command of the Listener Control Utility. For more information, see the section on Listener Administration in the Oracle Net Services Administrator's Guide.

3.1.7.3 User Action

Not applicable.

3.1.8 Version

The version of the listener software. On the Metric Detail page, you can see the value of this metric only when you select one of the Real Time refresh options. This metric also appears on the Enterprise Manager Listener home page.

3.1.8.1 Metric Summary

The following table shows how often the metric's value is collected.

Target Version	Collection Frequency
All Versions	Every 15 Minutes

3.1.8.2 Data Source

This metric is derived from the STATUS command of the Listener Control Utility. For more information, see the section on Listener Administration in the Oracle Net Services Administrator's Guide.

3.1.8.3 User Action

Not applicable.

3.2 Load

This metric is a container for a set of metrics that provide you with information about the number of connections supported by the Listener over a period of time.

3.2.1 Connections Established (per min)

This metric represents the average number of connections per minute that were established with the listener.

3.2.1.1 Metric Summary

The following table shows how often the metric's value is collected.

Target Version	Collection Frequency
All Versions	Every 15 Minutes

3.2.1.2 Data Source

This metric is derived from the Listener Control Utility. For more information, see the section on Listener Administration in the Oracle Net Services Administrator's Guide.

3.2.1.3 User Action

If you are noticing experiencing performance issues with the database or other services supported by the listener, review the historical values of this metric to determine whether or not the performance problems are caused by excessive load on the listener or host.

3.2.2 Connections Refused (per min)

This metric represents the average number of connections that were refused per minute. A connection can be refused for a variety of reasons, including situations where the database or other listener service is down, or if the connection timed out.

3.2.2.1 Metric Summary

The following table shows how often the metric's value is collected.

Target Version	Collection Frequency
All Versions	Every 15 Minutes

3.2.2.2 Data Source

This metric is derived from the Listener Control Utility. For more information, see the section on Listener Administration in the Oracle Net Services Administrator's Guide.

3.2.2.3 User Action

If Enterprise Manager reports a high number of refused connections, check the availability and performance of the database or other services supported by the listener.

3.3 Response

This metric is a container for the Response and Status metrics that provide you with performance information about the Listener.

3.3.1 Response Time (msec)

This metric represents the time (in milliseconds) that it takes for the Listener to respond to a network request (ping).

3.3.1.1 Metric Summary

The following table shows how often the metric's value is collected and compared against the default thresholds. The 'Consecutive Number of Occurrences Preceding Notification' column indicates the consecutive number of times the comparison against thresholds should hold TRUE before an alert is generated.

Table 3-1 Metric Summary Table

Target Version	Evaluation and Collection Frequency	Upload Frequency	Operator	Default Warning Threshold	Default Critical Threshold	Consecutive Number of Occurrences Preceding Notification	Alert Text
All Versions	Every 5 Minutes	After Every Sample	>	80	100	1	Listener response to a TNS ping is %value% msecs

3.3.1.2 Data Source

The value of this metric is derived using the TNSPING command. For mor information about the TNSPING command, see the Oracle Net Services Administrator's Guide.

3.3.1.3 User Action

If the Listener response time consistently exceeds the threshold, users are likely experiencing performance issues while accessing the database or other services on this host. Use the Enterprise Manager Central Console to review other performance indicators, such as the overall health of your database and the response time of your hosts and Web Applications.

3.3.2 Status

This metric returns a value of "1" if the Listener is up and running; it returns a 0 if the Listener is unavailable.

3.3.2.1 Metric Summary

Table 3-2 Metric Summary Table

Target Version	Evaluation and Collection Frequency	Upload Frequency	Operator	Default Warning Threshold	Default Critical Threshold	Consecutive Number of Occurrences Preceding Notification	Alert Text
All Versions	Every 5 Minutes	After Every Sample	=	Not Defined	0	1	The listener is down: %oraerr%.

3.3.2.2 Data Source

This metric is derived from the STATUS command in the Listener Control Utility. For more information, see the Oracle Net Services Reference Manual.

3.3.2.3 User Action

When the listener is down, users cannot access the database or other services on this host. Review the troubleshooting information in Oracle Net Services Administrator's Guide.