-- Informations on rollbacks
SELECT s.USERNAME, s.SID, s.SERIAL#, t.USED_UBLK, t.USED_UREC, rs.SEGMENT_NAME,
       r.RSSIZE, r.STATUS
FROM V$TRANSACTION t,
     V$SESSION s,
     V$ROLLSTAT r,
     DBA_ROLLBACK_SEGS rs
WHERE s.SADDR = t.SES_ADDR
  AND t.XIDUSN = r.USN
  AND rs.SEGMENT_ID = t.XIDUSN
ORDER BY t.USED_UBLK DESC;