QUESTION 64
These are the details about V$FLASHBACK_DATABASE_STAT:
SQL> DESC v$FLASHBACK_DATABASE_STAT
Name           Null?       Type
------------- -------- --------------
BEGIN_TIME                 DATE
END_TIME                   DATE
FLASHBACK_DATA            NUMBER
DB_DATA                   NUMBER
REDO_DATA                 NUMBER
ESTIMATED_FLASHBACK_SIZE  NUMBER
Which two statements regarding the V$FLASHBACK_DATABASE_STAT view are true? (Choose two.)
A. BEGIN_TIME is the time at which Flashback logging is enabled.
B. END_TIME is the time at which the query is executed on the view.
C. REDO_DATA is the number of bytes of redo data written during the interval.
D. This view contains information about flashback data pertaining to the last 24 hours.
E. FLASHBACK_DATA is the amount of flashback data generated since the database was opened.
Answer: CD

C肯定没有问题，但是D说不通哦，应该是由DB_FLASHBACK_RETENTION_TARGET决定的

问问，关注ing...

是CD沒錯

last 24 hours。。。。这个贴我也关注，，答案我是背的，，，为什么是24个小时，这个我也没明白

回答楼主的问题： db_flashback_retention_target 的默认值是1440（60*24），即1天

所以答案是  24小时。