DBA

Initialization Parameter Files :-

sql>Connect / as sysdba

sql>startup

* To start an instance, the Oracle server must read on the Initializtion parameter Files.

* Changes to entries in the file take effect based on the type of initialization parameter file used.

• Static Parameter file , PFILE ----> commonly refered as initSID.ora
• Persistent Parameter file , SPFILE ----> Commonly refered as spfileSID.ora

Parameter File Contents,

• A list of instance parameters.
• The name of the database instance assoiciated with
• Allocations for memory strutures of the System global area
• what to do with filled Online redo log files
• The names and locations of control files
• Information on undo segments.

PFILE :-

• The pfile is a text file .it maintained by standard operating system editor.
• Paramerter file is read only during instance startup.
• If the file is modified,the instance must be shutdown and restarted in order to make the new parameter effective.

SPFILE :-

• Binary file
• Maintained by oracle server
• Alter system command using to changes made

sql> alter system set uno_tablespace='undo2';

sql> alter system set parameter = value [scope =memory spfile both]

• Memory ---> Changes the parameter values only in the currently running file.
• Spfile ----> changes the parameter values only in the spfile.
• Both -----> Currently running the instnace and spfile.

Creating a spfile,

sql>create spfile from pfile;