Use of PFILE or SPFILE
When an Oracle instance is started, its characteristics are set by reading some initialization parameters. These parameters are specified either through PFILE or SPFILE.
When an Oracle instance is being started, it reads either PFILE or SPFILE to set its characteristics.
What is PFILE?
A PFILE is a static, client side text file. This file normally resides on the server. However in case,
you would like to start Oracle from a remote machine, you will need a local copy of the PFILE no that machine.
you would like to start Oracle from a remote machine, you will need a local copy of the PFILE no that machine.
This file can be edited with a standard text editor like notepad or vi editor. This file will be
commonly referred as INIT.ORA file.
commonly referred as INIT.ORA file.
What is SPFILE?
SPFILE (Server parameter file) is a persistent server side binary file. SPFILE should only be
modified through “ALTER SYSTEM SET” command . Editing an SPFILE directly will corrupt the file
and the start up of the database or instance will not be possible.
and the start up of the database or instance will not be possible.
As SPFILe is a server side binary file, local copy of the PFILE is not required to start oracle from
a remote machine.
a remote machine.
Advantages of SPFILE compared to PFILE
- A SPFILE doesnot need a local copy of the pfile to start oracle from a remote machine. Thus eliminates configuration problems.
- SPFILE is a binary file and modications to that can only be done through ALTER SYSTEM
- SET command.
- As SPFILE is maintained by the server, human errors can be eliminated as the parameters are checked before modification in SPFILE
- It is easy to locate SPFILE as it is stored in a central location
- Changes to the parameters in SPFILE will take immediate effect without restart of the instance i.e Dynamic change of parameters is possible
- SPFILE can be backed up by RMAN
Difference between PFILE and SPFILE in Oracle :
PFILE
|
SPFILE
|
|
| 1 | Static, client side text file | Persistent server side binary file |
| 2 | Local copy of pfile required to start database from a remote machine | local copy is not required |
| 3 | Can be edited through notepad or vi editor | Editing directly will corrupt the file. It should be modified only through ALTER SYSTEM SET command |
| 4 | Is available in earlier versions of Oracle 9i | Available from Oracle 9i and above |
| 5 | Prone to human errors while modification | Eliminates human errors as parameters are checked before modification |
| 6 | Cannot be backed up by RMAN | Can be backed up by RMAN |
| 7 | Parameters in pfile cannot be changed dynamically and system needs to be bounced for the new changes to take effect | Dynamic change of some parameters is possible. Need not restart server for the changes to take effect |
Query to check if the database is running with PFILE or SPFILE
Execute the following command in SQL command line find out if database is started with a PFILE or SPFILE.
SQL > SELECT DECODE(value, NULL, ‘PFILE’, ‘SPFILE’) “Init File” FROM sys.v_$parameter WHERE name = ‘spfile’;
