Oracle deadlocks - what happens?:
"# Oracle does not kill the session.
# Oracle does not kill the transaction.
# Oracle only kills the statement.
# Oracle does not rollback the statement.
# PMON (Process Monitor) does not clear out the locks.
It is the responsibility of the session that detects the “ORA-00060 deadlock detected while waiting for resource” error to trap and handle the error by issuing a rollback (or a commit) command. Only once this has been done will the other session be able to continue."