1. 查看当前正在只用的undo段 select s.sid, s.serial#, s.username, r.name, t.STATUS, t.START_TIME, t.USED_UBLK, t.cr_get, t.phy_io, t.used_ublk, t.noundo ,s.program from v$rollname r, v$transaction t, v$session s where t.addr=s.taddr and t.xidusn=r.usn order by…