Q
题目
The ORCL database has CONTROL FILE AUTOBACKUP and BACKUP OPTIMIZATION enabled.TBS1 and TBS2 are the only user-defined tablespaces in ORCL.USER1.EMP is able in TBS1.
Examine these commands:
$ rman target /
RMAN> BACKUP INCREMENTAL LEVEL 0 DATABASE;
RMAN> exit
$ sqlplus / as sysdba
SQL> UPDATE user1.emp SET sal=10000 WHERE eno=1;
1 row updated
SQL> COMMIT;
Commit complete.
SQL> ALTER TABLESPACE tbs1 READ ONLY;
Tablespace altered.
SQL> exit
$ rman target /
RMAN> BACKUP INCREMENTAL LEVEL 1 DATABASE;
From which files are modified blocks backed up?
A. SYSTEM and SYSAUX only
B. SYSTEM, SYSAUX, UNDO, TEMP, TBS1, and TBS2
C. SYSTEM, SYSAUX, and UNDO only
D. SYSTEM, SYSAUX, UNDO, and TBS1 only
E. SYSTEM, SYSAUX, UNDO, and TBS2 only
A
答案
Answer：D
全库备份，肯定不包括TEMP，一定包括TBS1，据此排除ABCE。
RMAN中的备份优化(Backup Optimization) 是指在备份过程中，如果满足特定条件，RMAN 将自动跳过某些文件而不将它们包含在备份集中以节省时间和空间。备份优化包括OFF和ON两个状态，默认为OFF：
打开备份优化：
CONFIGURE BACKUP OPTIMIZATION ON;
关闭备份优化：
CONFIGURE BACKUP OPTIMIZATION OFF;
on状态： Read-only datafiles will not be backed up as long as backups of those files already exist and those backups meet established retention criteria. 只读数据文件不会被备份，只要已经存在这些文件的备份，这些备份可满足既定的保留条件。
优化备份对offline/read only文件操作后有备份的下次会不包含在备份中。
