ts_undo

查看回滚段正在处理的事务
SELECT s.username,
       s.sid,
       pr.PID,
       s.OSUSER,
       s.MACHINE,
       s.PROGRAM,
       rs.segment_id,
       r.usn,
       rs.segment_name,      
       r.rssize/1024/1024,
       sq.sql_text
  FROM v$transaction t, v$session s, v$rollstat r, dba_rollback_segs rs ,v$sqltext  sq,v$process pr
WHERE s.saddr = t.ses_addr
   AND t.xidusn = r.usn 
   AND rs.segment_id = t.xidusn
   AND s.sql_address=sq.address
   AND s.sql_hash_value = sq.hash_value
   AND s.PADDR=pr.ADDR
ORDER BY t.used_ublk DESC ,sq.PIECE;

查看回滚段的使用情况：
SELECT TABLESPACE_NAME,STATUS,TRUNC(SUM(BLOCKS) * 8 / 1024) AS "Size M",
COUNT(*) Undo_Extent_Num
FROM DBA_UNDO_EXTENTS
GROUP BY TABLESPACE_NAME, STATUS;

查看回滚段争用情况：
select * from v$waitstat;
SELECT name, waits, gets, waits/gets "Ratio"
FROM v$rollstat a, v$rollname b
WHERE a.usn = b.usn;


查看回滚段的统计信息
SELECT n.name, s.extents, s.rssize, s.optsize, s.hwmsize, s.xacts, s.status
FROM v$rollname n, v$rollstat s
WHERE n.usn = s.usn;

查看回滚段回退信息：
select name,value from v$sysstat where name in('user commits','transaction rollbacks');