Performing Time-Based or Change-Based Incomplete Recovery

OCP 053:

192.What is the purpose of the until change option of the restore command?

A. It allows you to select the SCN that you want to restore to.

B. It allows you to select the log sequence number you want to restore to.

C. It allows you to select the timestamp you want to restore to.

D. It allows you to manually stop the restore at any time as online redo logs are applied.

E. None of the above.

Answer: A

答案解析：

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10642/osrecvry.htm#BRADV219

 

Performing Time-Based or Change-Based Incomplete Recovery

This section describes how to specify an SCN or time for the end point of recovery. If your database is affected by seasonal time changes (for example, daylight savings time), then you may experience a problem if a time appears twice in the redo log and you want to recover to the second, or later time. To handle time changes, perform cancel-based or change-based recovery.

To perform change-based or time-based recovery:

1. Follows Step 1 through Step 8 in "Performing Closed Database Recovery".

2. Issue the RECOVER DATABASE UNTIL statement to begin recovery. If recovering to an SCN, then specify as a decimal number without quotation marks. For example, to recover through SCN 10034 issue:

   RECOVER DATABASE UNTIL CHANGE 10034;

   If recovering to a time, then the time is always specified using the following format, delimited by single quotation marks: 'YYYY-MM-DD:HH24:MI:SS'. The following statement recovers the database up to a specified time:

   RECOVER DATABASE UNTIL TIME '2000-12-31:12:47:30'

3. Apply the necessary redo log files to recover the restored data files. The database automatically terminates the recovery when it reaches the correct time, and returns a message indicating whether recovery is successful.

   Note:

   Unless recovery is automated, the database supplies the name from LOG_ARCHIVE_DEST_1 and asks you to stop or proceed with after each log. If the control file is a backup, then after the archived logs are applied you must supply the names of the online logs.

4. Follow Steps 4 and 5 in "Performing Cancel-Based Incomplete Recovery".

 

UNTIL SCN integer

Specifies an SCN as an upper, noninclusive limit. RMAN selects only files that it can use to restore or recover up to but not including the specified SCN (seeExample 4-38). For example, RESTORE DATABASE UNTIL SCN 1000 chooses only backups that could be used to recover to SCN 1000.