select s.username, s.osuser, s.sid, s.serial#, p.spid
from v$session s,v$process p
where s.paddr = p.addr
and s.username is not null;
This will return the database username, the operating system username, the session id, the serial number, and the system process id (SPID). Then, a DBA user can issue the following (using the SID and SERIAL# information from the previous query):
ALTER SYSTEM KILL SESSION 'sid,serial#';
ALTER SYSTEM KILL SESSION '9,203';
