View locked objects

select
object_name,
object_type,
session_id,
type,                 
lmode,        
request,
block,
ctime                 
from
v$locked_object, all_objects, v$lock
where
v$locked_object.object_id = all_objects.object_id AND
v$lock.id1 = all_objects.object_id AND
v$lock.sid = v$locked_object.session_id
order by
session_id, ctime desc, object_name;

Example:


SQL> lock table ext_tab_db in exclusive mode;

Table(s) Locked.

Elapsed: 00:00:00.11
SQL> select
  2  object_name,
  3  object_type,
  4  session_id,
  5  type,
  6  lmode,
  7  request,
  8  block,
  9  ctime
 10  from
 11  v$locked_object, all_objects, v$lock
 12  where
 13  v$locked_object.object_id = all_objects.object_id AND
 14  v$lock.id1 = all_objects.object_id AND
 15  v$lock.sid = v$locked_object.session_id
 16  order by
 17  session_id, ctime desc, object_name;

OBJECT_NAME                    OBJECT_TYPE         SESSION_ID TY      LMODE
------------------------------ ------------------- ---------- -- ----------
   REQUEST      BLOCK      CTIME
---------- ---------- ----------
EXT_TAB_DB                     TABLE                       31 TM          6
         0          2          8


Elapsed: 00:00:00.17
SQL>