OCP-1Z0-053-V12.02-345题

 

345.What view might you use to try to determine how long a particular backup will take?

A. V$SESSION_EVENT

B. V$SESSION

C. V$WAITS

D. V$WAITSTAT

E. V$SESSION_LONGOPS

Answer: E

 答案解析：

参考如下：

sys@TEST1107> SELECT SID, SERIAL#, CONTEXT, SOFAR, TOTALWORK,

  2  ROUND(SOFAR/TOTALWORK*100,2) "%_COMPLETE"

  3  FROM V$SESSION_LONGOPS

  4  WHERE OPNAME LIKE 'RMAN%'

  5  AND OPNAME NOT LIKE '%aggregate%'

  6  AND TOTALWORK != 0

  7  AND SOFAR <> TOTALWORK;

       SID    SERIAL#    CONTEXT      SOFAR  TOTALWORK %_COMPLETE

---------- ---------- ---------- ---------- ---------- ----------

       189          7          1      31998      80640      39.68

       156         49          1      31870      92800      34.34

V$SESSION_LONGOPS displays the status of various operations that run for longer than 6 seconds (in absolute time). These operations currently include many backup and recovery functions, statistics gathering, and query execution, and more operations are added for every Oracle release.

To monitor query execution progress, you must be using the cost-based optimizer and you must:

• Set the TIMED_STATISTICS or SQL_TRACE parameters to true

• Gather statistics for your objects with the DBMS_STATS package