When Oracle engine starts an instance, it reads the initialization parameter file to determine the values of initialization parameters. Then, it allocates an SGA and creates background processes. At this point, no database is associated with these memory structures and processes.

Type of initialization file:

Static (PFILE) Persistent (SPFILE)

Text file Binary file

Modification with an OS editor Cannot Modified

Modification made manually Maintained by the Server



Initialization parameter file content:

* Instance parameter
* Name of the database
* Memory structure of the SGA
* Name and location of control file
* Information about undo segments
* Location of udump, bdump and cdump file

Creating an SPFILE:

Create SPFILE=’……………………..ORA’

From PFILE=’……………………..ORA’;

Note:

* Required SYSDBA Privilege.
* Execute before or after instance startup.