About Initialization Parameters

Initialization Parameters

- in short INIT parameters.

Managing an Oracle instance includes configuring parameters that affect the basic operation of the Oracle instance. These parameters are called initialization parameters.
The Oracle instance reads initialization parameters from a file at startup.

There are two types of parameter files.
- Server parameter file (SPFILE)
- Text initialization parameter file (PFILE)

SPFILE:
- a binary file that can be written to and read by the database.
- must not be edited manually.
- stored on the host computer on which Oracle Database is running.

PFILE:
- a text file that can be read by the Oracle instance, but it is not written to by the instance.
- You can change a PFILE with a text editor, but changes do not take effect until you restart the Oracle instance.

You can use SQL statements to create the following:

- A SPFILE from a PFILE.

SQL> create spfile from pfile;

- A SPFILE from the current (in-memory) values of all initialization parameters

- A PFILE from a SPFILE.

SQL> create pfile from spfile;

When you create the database with DBCA, a server parameter file is created. This file is then used each time the database is started.

The sample text initialization parameter file is named init.ora and is found in the following location on most platforms:

ORACLE_HOME/dbs

Viewing and Modifying Initialization Parameters

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