Prior to Oracle 8i, a listener was statically configured (listener.ora) to
service a given set of SIDs. From 8i, PMON dynamically registers a database
service with the listener.
Further, if the listener is running on the default TCP port of 1521, then
there is no need to configure a listener.ora at all.from Oracle 8i onwards, database instances can register themselves with
the Listener when started. Prior to this release, information about the
instance was required to be manually configured in the "listener.ora" file
in the form of a STATIC SID_LIST.
Database instance registration is comprised of two elements:
- Service registration provides the Listener with instance
information, such as database service names and instance
names.
- MTS (Shared Server) dispatcher registration provides dispatcher
information to the Listener.
By default, an instance background process registers instance information
to a Listener on the local machine. If a Listener is started after the
instance, there may be a delay before the instance and dispatchers are
registered (normally 30 to 35 seconds). As such, if a Listener receives an
incoming connection request before an instance is registered, the Listener
may reject the request with an ORA-12514 error. The instance will attempt to
register its services to the Listener periodically.
To disable auto registration add the local_listener parameter to the init<>.ora file or in the spfile to specify a dummy address.
PMON will reject the invalid address and will not attempt to register with port
1521.
It will be necessary to statically configure the SID_LIST_
for your instance if you disable dynamic registration.
