| Oracle® Database Net Services Administrator's Guide 10g Release 2 (10.2) Part Number B14212-02 |
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View PDF |
| Oracle® Database Net Services Administrator's Guide 10g Release 2 (10.2) Part Number B14212-02 |
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View PDF |
The listener is a separate process that runs on the database server computer. It receives incoming client connection requests and manages the traffic of these requests to the database server. This chapter describes how to configure the listener to accept client connections.
This chapter contains these topics:
See Also:
Chapter 3, "Connectivity Concepts" for a description of how the listener is used during an initial connection request
Chapter 5, "Architecture of Oracle Net Services" for an architectural overview of the listener
Note:
A version 10 listener is required for an Oracle Database 10g database. Previous versions of the listener are not supported for use with an Oracle Database 10g database. However, it is possible to use a version 10 listener with previous versions of the Oracle database.A listener is configured with one or more listening protocol addresses, information about supported services, and parameters that control its runtime behavior. The listener configuration is stored in a configuration file named listener.ora.
Because all of the configuration parameters have default values, it is possible to start and use a listener with no configuration. This default listener has a name of LISTENER, supports no services upon startup, and listens on the following TCP/IP protocol address:
(ADDRESS=(PROTOCOL=tcp)(HOST=host_name)(PORT=1521))
Supported services, that is, the services to which the listener forwards client requests, can be configured in the listener.ora file or this information can be dynamically registered with the listener. This dynamic registration feature is called service registration. The registration is performed by the PMON process—an instance background process—of each database instance that has the necessary configuration in the database initialization parameter file. Dynamic service registration does not require any configuration in the listener.ora file.
See Also:
"Listener Architecture"Service registration offers the following benefits:
Service registration reduces the need for the SID_LIST_listener_name parameter setting, which specifies information about the databases served by the listener, in the listener.ora file.
Note:
TheSID_LIST_listener_name parameter is still required if you are using Oracle Enterprise Manager to manage the database.Because the listener always knows the state of the instances, service registration facilitates automatic failover of the client connect request to a different instance if one instance is down.
In a static configuration model, a listener would start a dedicated server upon receiving a client request. The server would later find out that the instance is not up, causing an "Oracle not available" error message.
Runtime connection load balancing
Service registration enables the listener to forward client connect requests to the least loaded instance and dispatcher or dedicated server. Service registration balances the load across the service handlers and nodes.
Oracle Universal Installer launches Oracle Net Configuration Assistant during software installation. Oracle Net Configuration Assistant enables you to configure the listening protocol address and service information for an Oracle database.
During an Enterprise Edition or Standard Edition installation on the database server, Oracle Net Configuration Assistant automatically configures a listener with a name of LISTENER that has a TCP/IP listening protocol address for the Oracle database. During a Custom installation, Oracle Net Configuration Assistant prompts you to configure a listener name and a protocol address of your choice.
Additionally, a listening IPC protocol address for external procedure calls is automatically configured, regardless of the installation type.
Oracle Net Configuration Assistant also automatically configures service information for the external procedures in the listener.ora file.
Example 10-1 shows a listener.ora file sample. The LISTENER entry defines the listening protocol address for a listener named LISTENER, and the SID_LIST_LISTENER entry provides information about the services statically supported by the listener LISTENER.
Example 10-1 Example listener.ora File
LISTENER= (DESCRIPTION= (ADDRESS_LIST= (ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)(PORT=1521)) (ADDRESS=(PROTOCOL=ipc)(KEY=extproc)))) SID_LIST_LISTENER= (SID_LIST= (SID_DESC= (SID_NAME=plsextproc) (ORACLE_HOME=/oracle10g) (PROGRAM=extproc)))
If you are using the IPC protocol, you can improve performance by specifying the maximum number of concurrent IPC connection requests to match your expected connection requests. In listener.ora for example, you can specify the value as in the following example:
listener_name=(description=(address=(protocol=ipc)(key=listener0)(queuesize=50)))
See Also:
Oracle Database Net Services Reference for further information about identifying listeners by unique names and creating multiple listener entries in thelistener.ora fileIf the default or installed configuration is not adequate for a particular environment, you can use Oracle Net Manager to customize the listener.ora configuration.
This section contains these configuration topics:
To configure additional protocol addresses for the listener, use Oracle Enterprise Manager:
Access the Net Services Administration page in Oracle Enterprise Manager.
See Also:
"Oracle Enterprise Manager"Select Listeners from the Administer list, and then select the Oracle home that contains the location of the configuration files.
Click Go.
The Listeners page appears.
Select a listener, and then click Edit.
The Edit Listener page appears.
In the Addresses section, configure protocol support:
Click Add.
The Add Address page appears.
From the Protocol list, select the protocol on which the listener is configured to listen.
Enter the appropriate parameter information for the selected protocol in the fields provided.
When configuring the listener to listen on TCP/IP, you should enter the default port of 1521. If you do not, you must configure the LOCAL_LISTENER parameter in the intialization parameter file and resolve the listener name through a naming method.
See Also:
Oracle Database Net Services Reference for further information about protocol addresses and TCP/IP privileged ports
If the computer has more than one IP address and you want the listener to listen on all available IP addresses, configure TCP/IP or TCP/IP with SSL and enter the host name of the computer in the Host field.
Optionally, in the Advanced Parameters section, specify the I/O buffer space limit for send and receive operations of sessions in the Total Send Buffer Size and Total Receive Buffer Size fields.
See Also:
"Configuring I/O Buffer Space" for further informationClick OK.
The protocol address is added to the Addresses section.
Repeat Step 5 for additional protocols.
Note:
You can also configure additional listening addresses with Oracle Net Manager. See topic Create Listener Address in the online Help for further instruction.Clients access Enterprise JavaBeans (EJBs) and Common Object Request Broker Architecture (CORBA) applications, provided with the Oracle JServer option, in an Oracle8i database over an Inter-Orb Protocol (IIOP) connection. IIOP is an implementation of General Inter-Orb Protocol (GIOP) over TCP/IP. To support access to CORBA and EJB, you configure the listener with a protocol address with port 2481 for TCP/IP or port 2482 for TCP/IP with SSL.
To configure a protocol address for Oracle JServer in an Oracle Database 10g database:
Start Oracle Net Manager.
See Also:
"Oracle Net Manager"In the navigator pane, expand Local > Listeners.
Select a listener.
From the list in the right pane, select Listening Locations.
Click Add Address.
A new Address tab appears.
Select the TCP/IP or TCP/IP with SSL protocol from the Protocol list.
Enter the host name of the database in the Host field.
Enter port 2481 for TCP/IP in the Port field, or enter port 2482 for TCP/IP with SSL in the Port field.
Click Statically dedicate this address for JServer connections.
Choose File > Save Network Configuration.
The listener.ora file updates with the following:
listener=
(DESCRIPTION_LIST=
(DESCRIPTION=
(ADDRESS=(PROTOCOL=tcp)(HOST=sales1-server)(PORT=2481))
(PROTOCOL_STACK=
(PRESENTATION=giop)
(SESSION=raw))))
If you expect the listener to handle large volumes of concurrent connection requests, then you can specify a listener queue size for its TCP/IP or IPC listening endpoints. To specify the listener queue size, specify the QUEUESIZE parameter at the end of the protocol address with its value set to the expected number of concurrent requests. For example:
Example 10-2 listener.ora File with Queue Size
LISTENER=
(DESCRIPTION=
(ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)(PORT=1521)(QUEUESIZE=20)))
Note:
The default number of concurrent connection requests is operating-system specific. The defaults for TCP/IP on the Solaris Operating System and Windows follow:Solaris Operating System: 5
Windows NT 4.0 Workstation: 5
Windows NT 4.0 Server: 50
The listener uses the dynamic service information about the database and instance it has received through service registration before using statically configured information in the listener.ora file.
Static configuration is also required for other services, such as external procedures, Heterogeneous Services.
Table 10-1 describes static service settings that you can set in the listener.ora file.
Table 10-1 Static Service Settings in listener.ora
| Oracle Net Manager Field | listener.ora File Parameter | Description |
|---|---|---|
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Specifies the Oracle System Identifier (SID) of the instance. You can obtain the SID value from the |
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Identifies the database service. Can the following paragraph be removed? It seems to be relevant only to Oracle8 While processing a client connection request, the listener tries to match the value of this parameter with the value of the The value for this parameter is typically obtained from the combination of the |
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On UNIX, this setting is optional. Use it to specify the Oracle home location of the instance. Without this setting, the listener assumes its Oracle home for the instance. On Windows, this setting is ignored. The Oracle home specified by the |
Important:
If you are using connect-time failover or Transparent Application Failover (TAF), such as in an Oracle Real Application Cluster environment, then do not set theGLOBAL_DBNAME parameter.See Also:
"Configuring Service Registration" for more information about configuring dynamic service registration of Oracle databases
Chapter 13, "Enabling Advanced Features of Oracle Net Services" for more information about statically configuring the listener for external procedures and Heterogeneous Services
Oracle Enterprise Manager Advanced Configuration for further information about Oracle Enterprise Manager
To statically configure the listener:
Access the Net Services Administration page in Oracle Enterprise Manager.
See Also:
"Oracle Enterprise Manager"Select Listeners from the Administer list, and then select the Oracle home that contains the location of the configuration files.
Click Go.
The Listeners page appears.
Select a listener, and then click Edit.
The Edit Listener page appears.
Click the Static Database Registration tab, and then click Add.
The Add Database Service page appears. Enter the required information in the fields.
See Also:
Table 10-1 for a description of the fieldsClick OK.
Note:
You can also configure static service information with Oracle Net Manager. See topic Statically Configure Database Service Information in the online Help for further instruction.The following example shows an excerpt of a listener.ora file statically configured for a database service called sales.us.acme.com:
SID_LIST_listener= (SID_LIST= (SID_DESC= (GLOBAL_DBNAME=sales.us.acme.com) (SID_NAME=sales) (ORACLE_HOME=/u01/app/oracle/10g)))
Note:
If you are administering the listener remotely over an insecure network and require maximum security, configure the listener with a secure protocol address that uses the TCP/IP with SSL protocol. If the listener has multiple protocol addresses, ensure that the TCP/IP with SSL protocol address is listed first in thelistener.ora file.It is important to provide security through a password for the listener. With a password, privileged operations, such as saving configuration changes or stopping the listener, used from the Listener Control utility will require a password.
Use the Listener Control utility's CHANGE_PASSWORD command or Oracle Enterprise Manager to set or modify an encrypted password in the PASSWORDS_listener_name parameter in the listener.ora file. If the PASSWORDS_listener_name parameter is set to an unencrypted password, you must manually remove it from the listener.ora file prior to modifying it. If the unencrypted password is not removed, you will be unable to successfully set an encrypted password.
To set or modify an encrypted password with Oracle Enterprise Manager:
Access the Net Services Administration page in Oracle Enterprise Manager.
See Also:
"Oracle Enterprise Manager"Select Listeners from the Administer list, and then select the Oracle home that contains the location of the configuration files.
Click Go.
The Listeners page appears.
Select a listener, and then click Edit.
The Edit Listeners page appears.
Click the Authentication tab.
Click Require a password for listener operations.
Click OK.
Note:
You can also configure static service information with Oracle Net Manager. See topic Configure Password Authentication for the Listener in the online Help for further instruction.To set a new encrypted password with the CHANGE_PASSWORD command, issue the following commands from the Listener Control utility:
LSNRCTL> CHANGE_PASSWORD Old password: New password: takd01 Reenter new password: takd01 Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=tpc)(HOST=sales-server)(PORT=1521))) Password changed for LISTENER The command completed successfully LSNRCTL> SAVE_CONFIG Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=sales-server)(PORT=1521))) Saved LISTENER configuration parameters. Listener Parameter File /oracle/network/admin/listener.ora Old Parameter File /oracle/network/admin/listener.bak The command completed successfully
Bold denotes user input. The password is not displayed when entered.
To modify an encrypted password with the CHANGE_PASSWORD command:
LSNRCTL> SET PASSWORD Password: takd01 The command completed successfully LSNRCTL> CHANGE_PASSWORD Old password: takd01 New password: smd01 Reenter new password: smd01 Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=tpc)(HOST=sales-server)(PORT=1521))) Password changed for LISTENER The command completed successfully LSNRCTL> SAVE_CONFIG Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=sales-server)(PORT=1521))) Saved LISTENER configuration parameters. Listener Parameter File /oracle/network/admin/listener.ora Old Parameter File /oracle/network/admin/listener.bak The command completed successfully
See Also:
Oracle Database Net Services Reference for further information about theCHANGE_PASSWORD commandFor Oracle9i databases, the listener uses the dynamic service information about the database and instance it has received through service registrationbefore using statically configured information in the listener.ora file. Dynamic service registration is configured in the database initialization file. It does not require any configuration in the listener.ora file. However, listener configuration must be synchronized with the information in the database initialization file.
This section contains the following configuration topics related to service registration:
To ensure service registration works properly, the initialization parameter file should contain the following parameters:
SERVICE_NAMES for the database service name
INSTANCE_NAME for the instance name
For example:
SERVICE_NAMES=sales.us.acme.com INSTANCE_NAME=sales
The value for the SERVICE_NAMES parameter defaults to the global database name, a name comprising the DB_NAME and DB_DOMAIN parameters in the initialization parameter file, entered during installation or database creation. The value for the INSTANCE_NAME parameter defaults to the SID entered during installation or database creation.
See Also:
Oracle Database Reference for further information about theSERVICE_NAMES and INSTANCE_NAME parametersBy default, the PMON process registers service information with its local listener on the default local address of TCP/IP, port 1521. As long as the listener configuration is synchronized with the database configuration, PMON can register service information with a nondefault local listener or a remote listener on another node. Synchronization is simply a matter of specifying the protocol address of the listener in the listener.ora file and the location of the listener in the initialization parameter file.
If you want PMON to register with a local listener that does not use TCP/IP, port 1521, configure the LOCAL_LISTENER parameter in the initialization parameter file to locate the local listener.
For a shared server environment, you can alternatively use the LISTENER attribute of the DISPATCHERS parameter in the initialization parameter file to register the dispatchers with a nondefault local listener. Because both the LOCAL_LISTENER parameter and the LISTENER attribute enable PMON to register dispatcher information with the listener, it is not necessary to specify both the parameter and the attribute if the listener values are the same.
Set the LOCAL_LISTENER parameter as follows:
LOCAL_LISTENER=listener_alias
Set the LISTENER attribute as follows:
DISPATCHERS="(PROTOCOL=tcp)(LISTENER=listener_alias)"
listener_alias is then resolved to the listener protocol addresses through a naming method, such as a tnsnames.ora file on the database server.
For example, if the listener is configured to listen on port 1421 rather than port 1521, you can set the LOCAL_LISTENER parameter in the initialization parameter file as follows:
LOCAL_LISTENER=listener1
Using the same listener example, you can set the LISTENER attribute as follows:
DISPATCHERS="(PROTOCOL=tcp)(LISTENER=listener1)"
You can then resolve listener1 in the local tnsnames.ora as follows:
listener1= (DESCRIPTION= (ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)(PORT=1421)))
Notes:
To dynamically update the LOCAL_LISTENER parameter, use the SQL statement ALTER SYSTEM SET:
ALTER SYSTEM SET LOCAL_LISTENER='listener_alias'
If you set the parameter to null with the statement that follows, then the default local address of TCP/IP, port 1521 is assumed.
ALTER SYSTEM SET LOCAL_LISTENER=''
See the Oracle Database SQL Reference for further information about the ALTER SYSTEM SET statement.
The LISTENER attribute overrides the LOCAL_LISTENER parameter. As a result, the SQL statement ALTER SYSTEM SET LOCAL_LISTENER does not affect the setting of this attribute.
To register information with another local listener:
Configure the listener.ora file with the protocol address of the local listener.
Configure the LOCAL_LISTENER parameter in the initialization parameter file to locate the local listener. If you are using shared server, you can also use the LISTENER attribute of the DISPATCHERS parameter in the initialization parameter file.
Resolve the listener name alias for the LOCAL_LISTENER or the LISTENER setting through a tnsnames.ora file.
See Also:
"Configuring a Naming Method"Registration to remote listeners, such as in the case of Oracle Real Application Clusters, can be configured for shared server or dedicated server environments.
If you want PMON to register with a remote listener, configure the REMOTE_LISTENER parameter in the initialization parameter file to locate the remote listener.
For a shared server environment, you can alternatively use the LISTENER attribute of the DISPATCHERS parameter in the initialization parameter file to register the dispatchers with any listener. Because both the REMOTE_LISTENER parameter and the LISTENER attribute enable PMON to register dispatcher information with the listener, it is not necessary to specify both the parameter and the attribute if the listener values are the same.
Set the REMOTE_LISTENER parameter as follows:
REMOTE_LISTENER=listener_alias
Set the LISTENER attribute as follows:
DISPATCHERS="(PROTOCOL=tcp)(LISTENER=listener_alias)"
listener_alias is then resolved to the listener protocol addresses through a naming method, such as a tnsnames.ora file on the database server.
For example, if separate listeners are configured to listen on port 1521 on servers sales1-server and sales2-server, you can set the REMOTE_LISTENER parameter in the initialization file for the instance on host sales1-server as follows:
REMOTE_LISTENER=listener_sales2
You can set the REMOTE_LISTENER parameter in the initialization file for the instance on host sales2-server as follows:
REMOTE_LISTENER=listener_sales1
You can then resolve listener_sales2 in the local tnsnames.ora on sales1-server as follows:
listener_sales2= (DESCRIPTION= (ADDRESS=(PROTOCOL=tcp)(HOST=sales2-server)(PORT=1521)))
Likewise, you can resolve listener_sales1 in the local tnsnames.ora on sales2-server as follows:
listener_sales1= (DESCRIPTION= (ADDRESS=(PROTOCOL=tcp)(HOST=sales1-server)(PORT=1521)))
If shared server is configured, you can set the DISPATCHERS parameter in the initialization parameter file as follows:
DISPATCHERS="(PROTOCOL=tcp)(LISTENER=listeners_sales)"
You can then resolve listener_sales in the local tnsnames.ora as follows:
listeners_sales= (DESCRIPTION= (ADDRESS=(PROTOCOL=tcp)(HOST=sales1-server)(PORT=1521)) (ADDRESS=(PROTOCOL=tcp)(HOST=sales2-server)(PORT=1521)))
Notes:
To dynamically update the REMOTE_LISTENER parameter, use the SQL statement ALTER SYSTEM SET:
ALTER SYSTEM SET REMOTE_LISTENER='listener_alias'
If you set the parameter to null with the statement that follows, then PMON de-registers information with the remote listener with which it had previously registered information.
ALTER SYSTEM SET REMOTE_LISTENER=''
See the Oracle Database SQL Reference for further information about the ALTER SYSTEM SET statement.
The LISTENER attribute overrides the REMOTE_LISTENER parameter. As a result, the SQL statement ALTER SYSTEM SET REMOTE_LISTENER does not affect the setting of this attribute.
To register information with remote listener:
Configure the listener.ora file with the protocol addresses of the remote listeners.
In a shared server environment, configure the LISTENER attribute of the DISPATCHERS parameter or the REMOTE_LISTENER parameter in the initialization parameter file. In a dedicated server environment, configure the REMOTE_LISTENER parameter in the database initialization parameter file.
Resolve the listener name alias for the LISTENER or the REMOTE_LISTENER setting through a tnsnames.ora file.
See Also:
"Configuring a Naming Method"The listener name alias specified for the LOCAL_LISTENER parameter, REMOTE_LISTENER parameter, or LISTENER attribute can be resolved through a tnsnames.ora file.
For example, if LOCAL_LISTENER is set to listener1 and listener1 uses TCP/IP on port 1421, the entry in the tnsnames.ora file would be:
listener1= (ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)(PORT=1421))
Note:
Multiple addresses are supported, but connect-time failover and client load balancing features are not supported.See Also:
Chapter 13, "Enabling Advanced Features of Oracle Net Services" for further information about multiple address configurationOnce the listener is configured, the listener can be administered with the Listener Control utility or Oracle Enterprise Manager. This section describes some of the common administrative tasks for the listener, including the following topics:
See Also:
Oracle Database Net Services Reference for a complete listing of all the Listener Control utility commands
Oracle Enterprise Manager online Help
To stop or start a listener, use either the Listener Control utility or Oracle Enterprise Manager.
Note:
You can configure the listener to start automatically whenever the computer it is running on is restarted. See your operating-system specific documentation for details about establishing auto-restart.Listener Control Utility
To stop a listener from the command line, enter:
lsnrctl STOP [listener_name]
where listener_name is the name of the listener defined in the listener.ora file. It is not necessary to identify the listener if you are using the default listener, named LISTENER.
To start the listener from the command line, enter:
lsnrctl START [listener_name]
where listener_name is the name of the listener defined in the listener.ora file. It is not necessary to identify the listener if you are using the default listener, named LISTENER.
In addition to starting the listener, the Listener Control utility verifies connectivity to the listener.
Oracle Enterprise Manager
To start or stop a listener from Oracle Enterprise Manager:
Access the Net Services Administration page in Oracle Enterprise Manager.
See Also:
"Oracle Enterprise Manager"Select Listeners from the Administer list, and then select the Oracle home that contains the location of the configuration files.
Click Go.
The Listeners page appears.
Select a listener.
From the Actions list, select Start/Stop.
The Start/Stop page appears.
Depending upon the current status of the selected listener, the operation will be either Stop or Start. Click OK to perform the operation.
To show the current status of a listener, use either the STATUS command of the Listener Control utility or Oracle Enterprise Manager. The status output provides basic status information about a listener, including a summary of listener configuration settings, the listening protocol addresses, and a summary of services registered with the listener.
Listener Control Utility
The STATUS command provides basic status information about a listener, including a summary of listener configuration settings, the listening protocol addresses, and a summary of services registered with the listener.
To show the status the listener from the command line, enter:
lsnrctl STATUS [listener_name]
where listener_name is the name of the listener defined in the listener.ora file. It is not necessary to identify the listener if you are using the default listener, named LISTENER.
Oracle Enterprise Manager
To show the status of a listener from Oracle Enterprise Manager:
Access the Net Services Administration page in Oracle Enterprise Manager.
See Also:
"Oracle Enterprise Manager"Select Listeners from the Administer list, and then select the Oracle home that contains the location of the configuration files.
Click Go.
The Listeners page appears.
Select a listener.
From the Actions list, select Show Listener Control Status.
The Listener Control Status page appears.
After viewing the content, click OK.
The STATUS command generates output with the sections described in Table 10-2.
Table 10-2 Listener Control Utility STATUS Command
| Output Section | Description |
|---|---|
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Specifies the following:
|
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Lists the protocol addresses the listener is configured to listen on |
|
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Displays a summary of the services registered with the listener and the service handlers allocated to each service |
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Identifies the registered service |
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Specifies the name of the instance associated with the service along with its status and number of service handlers associated with the service Status can be one of the following:
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Example 10-3 shows example output of the STATUS command.
Example 10-3 Listener Control Utility's STATUS Command Output
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=net))) STATUS of the LISTENER ------------------------ Alias LISTENER Version TNSLSNR for Solaris: Version 10.1.0.2.0 Start Date 15-NOV-2003 20:22:00 Uptime 0 days 0 hr. 5 min. 22 sec Trace Level support Security OFF SNMP OFF Listener Parameter File /oracle/admin/listener.ora Listener Log File /oracle/network/log/listener.log Listener Trace File /oracle/network/trace/listener.trc Listening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=net))) (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)(PORT=1521))) (DESCRIPTION=(ADDRESS=(PROTOCOL=tcps)(HOST=sales-server)(PORT=2484))) Services Summary... Service "sales.us.acme.com" has 1 instance(s). Instance "sales", status READY, has 3 handler(s) for this service... Service "hr.us.acme.com" has 1 instance(s). Instance "hr", status READY, has 2 handler(s) for this service... The command completed successfully
The SERVICES command of the Listener Control utility provides detailed information about the services and instances registered with a listener and the service handlers allocated to each instance.
The SERVICES command generates output with the sections described in Table 10-3.
Table 10-3 Listener Control Utility SERVICES Command
| Output Section | Description |
|---|---|
|
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Identifies the registered service |
|
|
Specifies the name of the instance associated with the service |
|
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The status field indicates if the instance is able to accept connections.
|
|
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Identifies the name of the service handler. Dispatchers are named This section also identifies the following about the service handler:
Following this, additional information about the service handler displays, such as whether the service handler is a dispatcher, a local dedicated server, or a remote dedicated server on another node. |
Example 10-4 shows example output of the SERVICES command.
Example 10-4 Listener Control Utility's SERVICES Command Output
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=net)))
Services Summary...
Service "sales.us.acme.com" has 1 instance(s).
Instance "sales", status READY, has 3 handler(s) for this service...
Handler(s):
"DEDICATED" established:0 refused:0 state:ready
LOCAL SERVER
"D000" established:0 refused:0 current:0 max:10000 state:ready
DISPATCHER <machine: sales-server, pid: 1689>
(ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)(PORT=52414))
"D001" established:0 refused:0 current:0 max:10000 state:ready
DISPATCHER <machine: sales-server, pid: 1691>
(ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)(PORT=52415))
Service "hr.us.acme.com" has 1 instance(s).
Instance "hr", status READY, has 2 handler(s) for this service...
Handler(s):
"DEDICATED" established:0 refused:0 state:ready
LOCAL SERVER
"D000" established:0 refused:0 current:0 max:10000 state:ready
DISPATCHER <machine: sales-server, pid: 11326>
(ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)(PORT=58361))
The command completed successfully
This output shows that two database services, sales.us.acme.com and hr.us.acme.com, are registered with the listener.
Client connection requests to sales.us.acme.com are handled by two dispatchers named D000 and D001 and one dedicated server. All handlers have a status of ready, indicating that they are ready to receive connections.
Client connection requests to hr.us.acme.com are handled by one dispatcher named D001 and one dedicated server.
When you notice any of the following conditions, review and monitor the listener log file for the following:
Long connection establishment times
Connectivity problems and refusals
Unexpected shutdown of the listener that could indicate a denial-of-service attack
See Also:
"Analyzing Listener Log Files"