Oracle transactions deadlock
Deadlock (ORA-00060) are automatically resolved by Oracle and signalled in the alter.log.
Transactional locks have to solved manually. 
You can kill session from sql command line using:

SQL&gt; alter system kill session 'sid, serial#';


This will mark session for being killed whener it's possible. Sometime kill is not immediate. IF you want and immediate kill you can, on a unix system, run

kill -9 processid


This will kill immediatly the session forcing the PMON to rollback any uncommitted data. To retrieve processid (SPID) run:

SQL&gt; SELECT spid
FROM v$process
WHERE NOT EXISTS ( SELECT 1 FROM v$session WHERE paddr = addr);


A final note: in windows process is slightly different. To kill a session you have to run:

C:\&gt; orakill &lt;SID&gt; &lt;spid&gt; 

where &lt;SID&gt;  = the Oracle instance name (ORACLE_SID)
      &lt;spid&gt; = the thread id of the thread to kill