C.2 Static Services | Oracle Net8 Configuration and Troubleshooting


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	Oracle Net8 Configuration and Troubleshooting By Jonathan Gennick , Hugo Toledo
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	Appendix C. The listener.ora File

Prior to Oracle8 i , you had to specifically tell the listener about each database instance that you wanted it to know about. This was (and sometimes still is) done using a SID_LIST_ listener_name entry in listener.ora , which is commonly referred to as the static services section . The static services section consists of several nested parameters. They are described here in the order in which they are nested.

SID_LIST_listener_name

 SID_LIST_  listener_name  =    (    SID_LIST =    ...    )

Begins the section of listener.ora that defines static services for a listener. This tag must enclose a SID_LIST tag.

Examples

 SID_LIST_EXTERNAL_PROCEDURE_LISTENER =   (SID_LIST =     (SID_DESC =       (PROGRAM = extproc)       (SID_NAME = plsextproc)       (ORACLE_HOME = /s01/app/oracle/product/8.1.5)     )   ) SID_LIST_PRODLISTENER =   (SID_LIST =     (SID_DESC =       (GLOBAL_DBNAME = jonathan.gennick.org)       (ORACLE_HOME = E:\Oracle\Ora81)       (SID_NAME = JONATHAN)     )     (SID_DESC =       (GLOBAL_DBNAME = herman.gennick.org)       (ORACLE_HOME = e:\Oracle\Ora81)       (SID_NAME = HERMAN)     )   )

SID_LIST

 SID_LIST =    (SID_DESC...)    [(SID_DESC...)    ...]

Defines a list of database instances that the listener services. The listener monitors its assigned port addresses and listens for incoming connection requests to these instances. Oracle7 and Oracle8 instances need to be listed in the SID_LIST in order for the listener to service them. Oracle8 i databases register automatically with the listener and do not need to be explicitly listed.

SID_DESC

 SID_DESC=    [(GLOBAL_DBNAME =  global_database_name  )]    [(SID_NAME =  sid  )]    (ORACLE_HOME =  oracle_home_directory  )    [(PRESPAWN_MAX...)]    [(PRESPAWN_LIST...)]    [(PROGRAM =  executable_name  )]

Registers one database instance with the listener, and must be enclosed within a SID_LIST parameter. The GLOBAL_DBNAME and SID_NAME parameters are both optional, but at least one of the two must be included. Oracle7 clients connect to an instance using the SID, so include SID_NAME if you want to support such clients. Beginning with Oracle8, clients can connect using either the SID or the global database name , so you may want to include both in your static service definitions. To see which method a client is using, look at the CONNECT_DATA parameter in the client's tnsnames.ora file.

Parameters

global_database_name: The global name for the database. This is a combination of the DB_NAME and DB_DOMAIN initialization parameters, and it must also be one of the service names listed with the SERVICE_NAMES initialization parameter.
sid: The system identifier for the database instance. This usually is equivalent to the INSTANCE_NAME initialization parameter.
oracle_home_directory: The complete path to the Oracle Home directory for the instance in question. This should be the actual path . Do not use symbols such as $ORACLE_HOME here.
PRESPAWN_MAX...: Only has relevance if you are using prespawned dedicated server processes. See the PRESPAWN_MAX parameter.
PRESPAWN_LIST...: Only has relevance if you are using prespawned dedicated server processes. See the PRESPAWN_LIST parameter.
executable_name: Specifies the name of an executable to run. This parameter is not used for database services. It is used for services such as extproc , which allows you to invoke external C and C++ functions from PL/SQL. The named executable must exist in the bin directory underneath the specified Oracle Home directory. The SID_NAME and ORACLE_HOME parameters must also be specified when the PROGRAM parameter is used.

PRESPAWN_MAX

 PRESPAWN_MAX =  limit

Defines an upper limit on the number of prespawned dedicated server processes that may be created for an instance. This limit must at least be equal to the sum of the values for all the POOL_SIZE parameters (see PRESPAWN_DESC) for the instance.

PRESPAWN_LIST

 PRESPAWN_LIST =    (PRESPAWN_DESC...)    [(PRESPAWN_DESC...)    ...]

Encloses a list of PRESPAWN_DESC parameters. Each PRESPAWN_DESC parameter defines a number of prespawned dedicated server processes to use for a specific network protocol.

PRESPAWN_DESC

 PRESPAWN_DESC =    (PROTOCOL =  protocol  )    (POOL_SIZE =  number_of_  processes  )    (TIMEOUT =  minutes_to_death  )

Defines the number of prespawned dedicated server processes to be created for a specific network protocol. Prespawned dedicated server processes are always protocol-specific .

Parameters

protocol: Identifies the network protocol supported by these processes. Use one of the abbreviations shown in Table 3.1.

Table C.1. Network Protocol Abbreviations

Abbreviation	Protocol
TCP	TCP/IP
SPX	SPX
IPC	Interprocess Communications
NMP	Named Pipes

number_of_ processes: Specifies the number of dedicated server processes to create for the specified protocol. This is also the number that Oracle attempts to keep available for new connections. As processes are taken out of the pool and assigned to a user as the result of a connection request, new processes are added in order to maintain the pool size . However, the total number of prespawned processes in existence is always subject to the limit specified by PRESPAWN_MAX. Once that limit has been reached, the pool will not be replenished.
minutes_to_death: Specifies the number of minutes that a prespawned dedicated server process is allowed to live once it has been used and returned to the pool. After the specified number of minutes, the process is deleted. This mechanism allows the number of prespawned processes to shrink back down to the value specified for the pool size. See Chapter 4, for more details.


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