oracle uba and xid
oracle uba and xidoraclexid=undo段号.undo槽号.undo对应槽号被覆盖的次数uba=10位块号54位块号.sequence.last entry undo recordxidsqn:undo 的序列号type id1 id2当type=tx的时候,id1=16位xidusn(段号)+16位xidslot(槽号)id2=xidsqn当type=tm的时候,id1=object_id.id2=0