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 |