ORA-00027: Cannot Kill Current Session

Generally , This error occurs , when you are trying to kill your current session, which is not allowed. EXAMPLE: Get the sid and serial# for the current session.

SQL> select username,inst_id, sid, serial# FROM gV$SESSION WHERE audsid = userenv(‘sessionid’);
USERNAME INST_ID SID SERIAL#
—————————— ———- ———- ———-
SYSTEM 1 242 14

Try to kill the session from current session:
SQL> alter system kill session ‘242,14’ immediate;
alter system kill session ‘242,14’ immediate
*
ERROR at line 1:
ORA-00027: cannot kill current session