String 

INSTANCE_NAME = instance_id 

Static 

The instance's SID 

Note: The SID identifies the instance's shared memory on a host, but may not uniquely distinguish this instance from other instances. 

Any alphanumeric characters 

In an Oracle Parallel Server environment, multiple instances can be associated with a single database service. Clients can override Oracle's connection load balancing by specifying a particular instance by which to connect to the database. INSTANCE_NAME specifies the unique name of this instance.

In a single-instance database system, the instance name is usually the same as the database name.

See Also: Oracle8i Parallel Server Administration, Deployment, and Performance and Net8 Administrator's Guide for more information.