Kill a locked Session using SQL Develope or Toad.

Query All the Locked sessions using below SQL and based on your OBJECT find the session locking it

SELECT l.inst_id,
SUBSTR(L.ORACLE_USERNAME,1,8) ORA_USER,
SUBSTR(L.SESSION_ID,1,3) SID,
S.serial#,
SUBSTR(O.OWNER||’.’||O.OBJECT_NAME,1,40) OBJECT, P.SPID
OS_PID,
DECODE(L.LOCKED_MODE, 0,’NONE’,
1,’NULL’,
2,’ROW SHARE’,
3,’ROW EXCLUSIVE’,
4,’SHARE’,
5,’SHARE ROW EXCLUSIVE’,
6,’EXCLUSIVE’,
NULL) LOCK_MODE
FROM sys.GV_$LOCKED_OBJECT L
, DBA_OBJECTS O
, sys.GV_$SESSION S
, sys.GV_$PROCESS P
WHERE L.OBJECT_ID = O.OBJECT_ID
and l.inst_id = s.inst_id
AND L.SESSION_ID = S.SID
and s.inst_id = p.inst_id
AND S.PADDR = P.ADDR(+)
order by l.inst_id

OR

SELECT l.session_id||’,’||v.serial# sid_serial,
l.ORACLE_USERNAME ora_user,
o.object_name,
o.object_type,
DECODE(l.locked_mode,
0, ‘None’,
1, ‘Null’,
2, ‘Row-S (SS)’,
3, ‘Row-X (SX)’,
4, ‘Share’,
5, ‘S/Row-X (SSX)’,
6, ‘Exclusive’,
TO_CHAR(l.locked_mode)
) lock_mode,
o.status,
to_char(o.last_ddl_time,’dd.mm.yy’) last_ddl
FROM dba_objects o, gv$locked_object l, v$session v WHERE o.object_id = l.object_id and l.SESSION_ID=v.sid
order by 2,3;

Kill the Session using the following fromat

ALTER SYSTEM KILL SESSION ‘sid,serial#’ IMMEDIATE;

Example:

ALTER SYSTEM KILL SESSION ‘25,29012’ IMMEDIATE;

ALTER SYSTEM KILL SESSION ‘21,7943’ IMMEDIATE;