oracle-oracle崩溃恢复预估恢复时间

数据库崩溃恢复时，查看回滚中的事务及预估时间

SELECT inst_id,
       usn,
       state,
       pid,
       xid,
       undoblockstotal "Total",
       undoblocksdone "Done",
       undoblockstotal - undoblocksdone "ToDo",
       decode(cputime,
              0,
              'unknown',
              to_char(SYSDATE + (((undoblockstotal - undoblocksdone) /
                      (undoblocksdone / cputime)) / 86400),
                      'yyyy-mm-dd hh24:mi:ss')) "Estimated time to complete"
  FROM gv$fast_start_transactions;

select * from gV$FAST_START_SERVERS;