OCP-1Z0-053-V13.02-329题

 

329.If you find errors in the view V$DATABASE_BLOCK_CORRUPTION with a status of

MEDIA_CORRUPT, what RMAN command would you run to correct the problem?

A. recover lost blocks;

B. recover corrupt blocks;

C. recover media corrupt blocks from list;

D. recover corrupt blocks from list;

E. recover corruption list;

Answer: E

答案解析：

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmblock.htm#BRADV360

Recovering All Blocks in V$DATABASE_BLOCK_CORRUPTION

In this scenario, RMAN automatically recovers all blocks listed in the V$DATABASE_BLOCK_CORRUPTION view.

To recover all blocks logged in V$DATABASE_BLOCK_CORRUPTION:

1. Start SQL*Plus and connect to the target database.

2. Query V$DATABASE_BLOCK_CORRUPTION to determine whether corrupt blocks exist. For example, execute the following statement:

   SQL> SELECT * FROM V$DATABASE_BLOCK_CORRUPTION;

3. Start RMAN and connect to the target database.

4. Recover all blocks marked corrupt in V$DATABASE_BLOCK_CORRUPTION.

   The following command repairs all physically corrupted blocks recorded in the view:

   RMAN>  RECOVER CORRUPTION LIST;

   After the blocks are recovered, the database removes them from V$DATABASE_BLOCK_CORRUPTION.

   
   

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10643/rcmsynta2001.htm#RCMRF90251

ORRUPTION LIST

Recovers all physically corrupt blocks listed in the V$DATABASE_BLOCK_CORRUPTION view. Block media recovery may not be able to repair all listed logically corrupt blocks. In these cases, alternate recovery methods, such as tablespace point-in-time recovery, or dropping and re-creating the affected objects, may repair the corruption. The V$DATABASE_BLOCK_CORRUPTION view displays blocks marked corrupt by Oracle Database components such as RMAN commands, ANALYZE, dbv, SQL queries, and so on. In short, any process that encounters an ORA-1578error records the block corruption in this view. The following types of corruption result in rows added to this view: Physical corruption (sometimes called media corruption). The database does not recognize the block at all: the checksum is invalid, the block contains all zeros, or the header and footer of the block do not match. Logical corruption. The block has a valid checksum, the header and footer match, and so forth, but the contents are logically inconsistent. The view does not record corruptions that can be detected by validating relationships between blocks and segments, but cannot be detected by a check of an individual block. Note: Any RMAN command that fixes or detects that a block is repaired updates V$DATABASE_BLOCK_CORRUPTION. For example, RMAN updates the repository at end of successful block media recovery. If a BACKUP, RESTORE, orVALIDATE command detects that a block is no longer corrupted, then it removes the repaired block from the view.