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Tuesday, November 15, 2011

Types of initialization parameter file




Oracle uses a parameter file to store the initialization parameters and their settings for an instance. We can use either of the following two types of parameter files:
  1. Server parameter file (SPFILE): Dynamic persistent server parameter file SPFILE, commonly referred as spfileSID.ora A binary file that contains the initialization parameters
  2. Initialization parameter file (pfile): Static parameter file, PFILE, commonly referred as initSID.ora  A text file that contains a list of all initialization parameters.

Contents Of Parameter File

A list of instance parameters
The name of the database the instance is associated with
Allocation for memory structures of the SGA
What to do with filled online redo log files.  (Archive Destination)
The names and locations of control files.
Information about undo tablespace.

 Text initialization parameter file:  PFILE à   initsid.ora  (sid) means database name

Text File
Modified with an operating system editor
Modification made manually
Whenever we need to change the value of the parameter file we must shutdown the database.
The pfile is read only during instance startup. (Changes take effect on next startup)

For oracle 10g (R2)   à  default location E:\oracle\product\10.2.0\Db_1\database\initorcl.ora

Server parameter file:  SPFILE : à spfilesid.ora  à   (sid)  means database name

- Binary File
- Maintained by the oracle server
- Always resides on the server side having read and write by database server
- Ability to make changes persistent across SHUTDOWN and STARTUP
- Can self-tune parameter values
- Can have RMAN support for backup the initialization parameter



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