Enable Disable Restricted Oracle Database Session

 SQL> shut immediate;

ORA-01507: database not mounted

SQL> startup mount restrict;

ORA-32004: obsolete or deprecated parameter(s) specified for RDBMS instance

ORACLE instance started.

Total System Global Area 3154113880 bytes

Fixed Size                  9139544 bytes

Variable Size            2080374784 bytes

Database Buffers         1040187392 bytes

Redo Buffers               24412160 bytes

Database mounted.

SQL> drop database;

Database dropped.

Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production

Version 19.15.0.0.0

SQL> startup restrict 

ORACLE instance started.

ALTER SYSTEM ENABLE RESTRICTED SESSION;

Command will put the db in restricted session.  

all users with the CREATE SESSION system privilege can connect to an open database. 

Opening a database in restricted mode allows database access only to users with both the CREATE SESSION 

and RESTRICTED SESSION system privilege; 

Start an instance (and, optionally, mount and open the database) in restricted mode by using the 

STARTUP command with the RESTRICT option:

STARTUP RESTRICT;

           SQL> alter system enable restricted session;

       system altered

 

       SQL> alter system disable restricted session;

system altered

SQL> alter system set resource_manager_plan=system_plan;

...

SQL> shutdown immediate;

...

SQL> startup

...

Database open

           SQL> alter system quiesce restricted;

             SQL> alter system unquiesce;

in quiesce mode only member of the internal group can have active sessions and these member are SYS and SYSTEM

SQL> SELECT logins from v$instance;

LOGINS

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RESTRICTED