ORA-12721: operation cannot execute when other sessions are active

Question

Hi,
I started my DB like following :
1) Change INIT.ORA file;  unset parallel_server parameter.
2) Execute these commands:
STARTUP MOUNT ;
ALTER SYSTEM ENABLE RESTRICTED SESSION;
ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0;
ALTER SYSTEM SET AQ_TM_PROCESSES=0;
ALTER DATABASE OPEN;
SHUTDOWN IMMEDIATE;
SQL> STARTUP RESTRICT  pfile='C:\oracle\product\10.2.0\db_1\database\initORCL.ora';
ORACLE instance started.
SQL> alter database national character set INTERNAL_CONVERT UTF8;
alter database national character set INTERNAL_CONVERT UTF8
ERROR at line 1:
ORA-12721: operation cannot execute when other sessions are activeWhy this error when DB is opened in strict and I'm the only user ?
SQL> select count (*) from v$session;
  COUNT(*)
        20Any solution ?
Thank you.

Answer 1

Hi
This operation is dangerous, please ensure that you have a full backup before doing that operation.
Please use that order :
SHUTDOWN IMMEDIATE;
-- make sure there is a database backup you can rely on, or create one
STARTUP MOUNT;
ALTER SYSTEM ENABLE RESTRICTED SESSION;
ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0;
ALTER SYSTEM SET AQ_TM_PROCESSES=0;
ALTER DATABASE OPEN;
ALTER DATABASE CHARACTER SET <new_character_set>;
-- a alter database takes typically only a few minutes or less,
-- it depends on the number of columns in the database, not the
-- amount of data.
SHUTDOWN;
Please note that :
The command requires the database to be
open but only one session, the one executing the command, is allowed.
For the above error conditions Oracle9i will report one of the errors:
ORA-12719: operation requires database is in RESTRICTED mode
ORA-12720: operation requires database is in EXCLUSIVE mode
ORA-12721: operation cannot execute when other sessions are active
Oracle9i can also report:
ORA-12718: operation requires connection as SYS
if you are not connect as SYS (INTERNAL, "/ AS SYSDBA").
Let us know if this helps.
regards,
Hub
Edited by: Hub on Dec 10, 2008 1:22 PM