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  • OCP-1Z0-053-V12.02-667题

    667.What does the DB_FLASHBACK_RETENTION_TARGET parameter configure?

    A. An upper limit on how far you can flash back the database, depending on the information in the redo

    logs

    B. An upper limit on how far you can flash back the database, depending on the information in the undo

    tablespace

    C. The amount of time for which the flashback data is to be kept in the flash recovery area, provided that

    there is enough space

    D. The amount of time for which the flashback data is guaranteed to be kept in the undo tablespace,

    provided that there is enough space

    Answer: C

    答案解析

    默认值 1440分钟

    改变:ALTER SYSTEM ... SID='*'

    ys@TEST0910> show parameter DB_FLASHBACK_RETENTION_TARGET
     
    NAME                                 TYPE        VALUE
    ------------------------------------ ----------- ------------------------------
    db_flashback_retention_target        integer     1440
     
    sys@TEST0910> alter system set DB_FLASHBACK_RETENTION_TARGET=1500;
     
    System altered.
     
    sys@TEST0910> show parameter DB_FLASHBACK_RETENTION_TARGET
     
    NAME                                 TYPE        VALUE
    ------------------------------------ ----------- ------------------------------
    db_flashback_retention_target        integer     1500
     

    DB_FLASHBACK_RETENTION_TARGET specifies the upper limit (in minutes) on how far back in time the database may be flashed back. How far back one can flashback a database depends on how much flashback data Oracle has kept in the fast recovery area.

    官方参考:http://docs.oracle.com/cd/E11882_01/server.112/e40402/initparams061.htm#sthref198

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  • 原文地址:https://www.cnblogs.com/hzcya1995/p/13317204.html
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