====== Monitor progress of UNDO operation ======

  select ses.username
	, substr(ses.program, 1, 19) command
	, tra.used_ublk
  from v$session ses, v$transaction tra
  where ses.saddr = tra.ses_addr;
  
  
 Source [[https://gavinsoorma.com/2009/06/how-to-monitor-the-progress-of-an-undo-operation/]]