Oracle Database Tips by Donald Burleson

Oracle10g Grid Computing with RAC
Chapter 8 - RAC Administration

Server Parameter File

A server parameter file is initially built from the traditional text initialization parameter file, using the create SPFILE statement. It is a binary file that cannot be browsed or edited with a text editor. Oracle provides other interfaces for viewing and modifying parameter settings.

At system startup, the default behavior of the STARTUP command is to read a SPFILE to obtain initialization parameter settings. If the STARTUP command doesn't have a PFILE clause, it reads the SPFILE from a location specified by the operating system. If you choose to use the traditional text initialization parameter file, you must specify the PFILE clause when issuing the STARTUP command.

Setting the Server Parameter File Values

Use the SID designator to set instance-specific parameter values in the server parameter file. For settings across the database, use a '*', and for a specific instance, set the prefix with SID as indicated below.

*.OPEN_CURSORS=300 # For database-wide setting
RACDB1.OPEN_CURSORS=1500 # For RACDB1 instance

Note that even though open_cursors is set at 300 for all instances in the first entry, the value of 1500 remains in effect for the SID 'RACDB1'.

Some initialization parameters are dynamic since they can be modified using the ALTER SESSION or ALTER SYSTEM statement while an instance is running. Use the following syntax to dynamically alter initialization parameters: