Restricted mode of instance

What is Restricted Mode of Instance Startup?



We can start an instance and mount and open a database in restricted mode so that the database is available only to DBAs.
Below are some reasons why we prefer Restricting mode  of instance:

    While performing export or import of database data(this is optional)
    While performing data load (with SQL*Loader)
    To Temporarily prevent users from using data
    During certain migration and upgrade operations

A normal cannot connect to the database which is in restricted mode ,but it can be made possible if RESTRICTED SESSION system privilege is provided to him.It is not recommended to provided RESTRICTED SESSION system privilege to normal user apart from DBAs.


Starting up an instance in restricted mode by using the command:
STARTUP RESTRICT
SQL> select logins from v$instance; --->to know the status of restricted mode.

Changing the restricted mode to normal mode by using the command:
ALTER SYSTEM DISABLE RESTRICTED SESSION;



cheers...!!!