Lesson 2	Configuring the dispatchers for MTS, part 1
Objective	Identify the dispatcher parameters.

Identify the Dispatcher Parameters used with Oracle

While there are only a handful of init.ora parameters that govern Shared Server, they all work closely together. The init.ora parameters required to initialize the MTS are:

shared_pool_size
mts_listener_address
mts_service
mts_dispatchers
mts_max_dispatchers
mts_servers
mts_max_servers

We will look closely at the first three parameters in this lesson, and at the remaining four in the next lesson.

Allocate additional Shared Pool Space

When users connect to the database via Shared Server, Oracle needs to allocate additional space in the shared pool for storing information about the connections between the user processes, dispatchers, and servers. For each user who will connect via Shared Server, you must add 1KB to the setting of the parameter shared_pool_size.

Specify address of listener

The Shared Server_listener_address parameter specifies the address of the listener and shows each port to which the database may connect. For example, in the following syntax, addr is an address at which the listener will listen for connection requests for a specific protocol.

Shared Server_LISTENER_ADDRESS = "(addr)"

View the code below to see multiple addresses contained in the init.ora file.

dilbert:[/u/oracle] > ps -ef|grep ora_d0

  oracle 19236     1   0 07:42:15      -  0:00 ora_d001_fred 
  oracle 29520     1   0 07:42:15      -  0:00 ora_d000_fred 
  oracle 30084 32034   1 07:47:09  pts/7  0:00 grep ora_d0 
  oracle 33642     1   0 07:42:15      -  0:00 ora_d002_fred

Each address specified in the database's parameter file must also be specified in the corresponding listener's configuration file. You specify addresses differently for various network protocols.

Specify Name of Service

You use the Shared Server_service parameter to specify the name of the service associated with dispatchers. A user requests Shared Server by specifying this service name in the connect string.
A service name must be unique; if possible, use the instance's SID (system identifier). For example, if the dispatcher's service name were fred, you would set the Shared Server_service parameter as follows:

Shared Server-service

Shared Server_SERVICE = "fred"

Once the Shared Server_service has been defined, you can specify a connect string for connecting to this dispatcher:

SQLPLUS system/manager@\
    (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(NODE=dilbert)\
    (OBJECT=outa))(CONNECT_DATA=(SID=fred)))

If you do not set the Shared Server_SERVICE parameter, its value defaults to the DB_NAME parameter.
If DB_NAME is also not set, Oracle returns the error ORA-00114, "missing value for system parameter Shared Server_service," when you start the database.
The next lesson investigates the remaining dispatch parameters.