Oracle: V$SESSION_BLOCKERS

select
   sbl.wait_id,
   sbl.wait_event,
   ses_blocked.username                blocked_username,
   ses_blocked.osuser                  blocked_osuser,
-- ses_blocked.event                   blocked_event,
   sbl.wait_event,   
   sql_blocked.sql_text,
   ses_blocked.sql_exec_start          blocked_sql_exec_start,
   ses_blocked.seconds_in_wait,
   ses_blocked.program                 blocked_program,   
   ses_blocked.module                  blocked_module,
   --------------------------------------
   ses_blocker.username                blocker_username,
   ses_blocker.osuser                  blocker_osuser,
   ses_blocker.event                   blocker_event,
   ses_blocker.sql_exec_start          blocker_sql_exec_start,
   ses_blocker.program                 blocker_program,   
   ses_blocker.module                  blocker_module,   
   sbl.sid                             blocked_sid,      
   sbl.blocker_sid,
   ses_blocked.final_blocking_session,
   sbl.blocker_sess_serial#,
   sbl.sess_serial#                    blocked_sess_serial#,
   sbl.wait_event_text,
   --------------------------------------
   sbl.blocker_instance_id,
   sbl.con_id
from
   v$session_blockers        sbl                                                            join
   v$session                 ses_blocked  on sbl.sid            = ses_blocked.sid           join
   v$session                 ses_blocker  on sbl.blocker_sid    = ses_blocker.sid      left join
   v$sqlarea                 sql_blocked  on ses_blocked.sql_id = sql_blocked.sql_id;