#####如何dump指定事务的undo信息 查出当前事务的usn号 select XIDUSN, XIDSLOT, XIDSQN, UBABLK,UBAFIL,UBAREC from v$transaction; SQL> select XIDUSN, XIDSLOT, XIDSQN, UBABLK,UBAFIL,UBAREC from v$transaction; XIDUSN XIDSLOT XIDSQN UBABLK UBAFIL UBAREC ---------- ---------- ---------- ---------- ---------- ---------- 9 40 343 139 2 16 查出当前事务的undo回滚段 select name from v$rollname where usn=9; 开始dump oradebug setmypid alter system dump undo block '_SYSSMU9$' xid 9 40 343; oradebug tracefile_name