Oracle static registration and dynamic registration

One, what is registration?

Registration is the registration of the database as a service to the listener. The client does not need to know the database name and instance name, just know that the database can be used to connect to the database with the service name provided externally. This service name may or may not be the same as the instance name.

During the database server startup process, the database server registers the appropriate service with the listener (whenever a database is started, two messages are registered to the listener by default): The database server's corresponding instance and service. ）

This is equivalent to: there is a listener (Listener) between the database server and the client, and in the Listener, the corresponding service name (one database may have multiple service names) is logged, and when the client needs to connect to the database, only the service name is provided. You can establish a connection between the client and the server.

Second, static registration

Static registration is the configuration that reads the Listener.ora file when the instance is started, registering the instance and service to the listener. Whenever you start a database, two messages are registered to the listener by default: the instance and service corresponding to the database server.

When statically registered, the Global_dbname in Listener.ora provides the service name, and the Sid_name in Listener.ora provides the registered instance name.

When a static registration method is adopted, the contents of the Listener.ora are as follows:

SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = D:\oracle\product\10.2.0\db_1)
(PROGRAM = extproc)
)
(SID_DESC =
(GLOBAL_DBNAME =orcl)
(ORACLE_HOME = D:\oracle\product\10.2.0\db_1)
(SID_NAME =orcl)
)
(SID_DESC =
(GLOBAL_DBNAME =orcl1)
(ORACLE_HOME = D:\oracle\product\10.2.0\db_1)
(SID_NAME =orcl)
)
)

This file indicates that the database is single-instance, with an instance named ORCL, providing two services outside: ORCL and ORCL1