V$LOCKED_OBJECT

Oracle 11gR1

V$LOCKED_OBJECT lists all locks acquired by every transaction on the system. It shows which sessions are holding DML locks (that is, TM-type enqueues) on what objects and in what mode.

Column	Datatype	Description
XIDUSN	NUMBER	Undo segment number
XIDSLOT	NUMBER	Slot number
XIDSQN	NUMBER	Sequence number
OBJECT_ID	NUMBER	Object ID being locked
SESSION_ID	NUMBER	Session ID
ORACLE_USERNAME	VARCHAR2(30)	Oracle user name
OS_USER_NAME	VARCHAR2(30)	OS user name
PROCESS	VARCHAR2(12)	OS process ID
LOCKED_MODE	NUMBER	Lock mode

Note:

1. Show locked objects

select oracle_username || ' (' || s.osuser || ')' username , s.sid || ',' || s.serial# sess_id , owner || '.' || object_name object , object_type , decode( l.block , 0, 'Not Blocking' , 1, 'Blocking' , 2, 'Global') status , decode(v.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(lmode)) mode_held from v$locked_object v , dba_objects d , v$lock l , v$session s where v.object_id = d.object_id and v.object_id = l.id1 and v.session_id = s.sid order by oracle_username , session_id;

Oracle dynamic performance views

Oracle data dictionary views