Oracle in a Nutshell

SPFILE: The Server Parameter File

Beginning with Oracle9i, Oracle introduced the concept of the server parameter file. This file, known as SPFILE , differs from the standard INIT.ORA file in a number of ways:

• It is a binary file, rather than a text-based file.

• It is stored on the server, rather than on a client machine.

• It can maintain changes to parameter values over the shutdown and startup of an instance.

This last point is the important part of SPFILE. If your database is running under Oracle9i, any changes you make to configuration parameters via the ALTER SYSTEM statement will be saved as part of the permanent configuration file. That means that if you change any of your database parameter values for tuning purposes, you won’t also have to change one or more INIT.ORA files so that the new values will persist. You also have the option of making dynamic changes to parameters without making them a part of the SPFILE; you do this by including the SCOPE clause in the ALTER SYSTEM statement, using the following syntax:

ALTER SYSTEM SET parameter_name = parameter_value 
   SCOPE = {MEMORY | SPFILE | BOTH};

For a complete description of the ALTER SYSTEM syntax, see Chapter 7.

With Oracle9i, you can still use a local INIT.ORA file by specifying the location of that file with a PFILE=name clause in the STARTUP statement. Oracle9i also provides a simple way to migrate the parameters in an existing INIT.ORA file to the binary SPFILE for an instance. You can copy the INIT.ORA file to the server machine ...