Killing a session in Oracle
Sessions in oracle can be killed with the command:
SQL> alter system kill session 'sid,serial#';
The value for sid and serial# can be query'd using the following query:
select * from v$session
select sid, serial#, osuser, program
After this command, the indicated session is marked for kill. When it's possible the session will be killed.
Sometimes this can take a while (for example when a lot of rollback is needed).
To kill a session faster you can use the keyword IMMEDIATE like this:
SQL> alter system kill session 'sid,serial#' immediate;