OCP-1Z0-053-V13.02-325题

 

325.Which of the following are valid until command options when attempting point-in-time recovery in

RMAN? (Choose all that apply.)

A. until time

B. until change

C. until sequence

D. until SCN

E. until commit

Answer: ACD

答案解析：

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10643/rcmsubcl019.htm#RCMRF160

 

Semantics

Syntax Element	Description
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.
UNTIL SEQUENCE integer	Specifies a redo log sequence number and thread as an upper, noninclusive limit. RMAN selects only files that it can use to restore or recover up to but not including the specified sequence number. For example, REPORT OBSOLETE UNTIL SEQUENCE 8000 reports only backups that could be used to recover through log sequence 7999.
THREAD integer	Specifies the number of the redo thread.
UNTIL TIME 'date_string'	Specifies a time as an upper, noninclusive limit (see Example 4-39). RMAN selects only files that it can use to restore and recover up to but not including the specified time. For example, LIST BACKUP UNTIL TIME 'SYSDATE-7' lists all backups that could be used to recover to a point one week ago. When specifying dates in RMAN commands, the date string must be either: A literal string whose format matches the NLS_DATE_FORMAT setting. A SQL expression of type DATE, for example, 'SYSDATE-10' or "TO_DATE('01/30/2007', 'MM/DD/YYYY')". The second example includes its own date format mask and so is independent of the currentNLS_DATE_FORMAT setting. Following are examples of typical date settings in RMAN commands: BACKUP ARCHIVELOG FROM TIME 'SYSDATE-31' UNTIL TIME 'SYSDATE-14'; RESTORE DATABASE UNTIL TIME "TO_DATE('09/20/06','MM/DD/YY')"; Note: The granularity of time-based recovery is dependent on time stamps in the redo log. For example, suppose that you specify the following command: RECOVER DATABASE UNTIL TIME '2007-07-26 17:45:00'; If no redo was written with a time stamp of 17:45:00, then recovery proceeds until it finds the next redo time stamp that is higher. For example, the next redo time stamp may be 17:45:04. You can check for the nearest time for a specific SCN by querying the FIRST_TIME and FIRST_CHANGE# columns in V$LOG_HISTORY TABLE.

Examples

Example 4-38 Performing Incomplete Recovery to a Specified SCN

This example, which assumes a mounted database, recovers the database up to (but not including) the specified SCN:

STARTUP FORCE MOUNT

RUN

{

  SET UNTIL SCN 1418901;  # set to 1418901 to recover database through SCN 1418900

  RESTORE DATABASE;

  RECOVER DATABASE;

}

ALTER DATABASE OPEN RESETLOGS;

Example 4-39 Reporting Obsolete Backups

This example enables you to recover to any point within the last week. It considers as obsolete all backups that could be used to recover the database to a point one week ago:

REPORT OBSOLETE UNTIL TIME 'SYSDATE-7';