8.RMAN备份EXAMPLE表空间

RMAN> backup tablespace EXAMPLE;

Starting backup at 21-DEC-16
using channel ORA_DISK_1
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00005 name=/u01/app/oracle/oradata/PROD1/example01.dbf
channel ORA_DISK_1: starting piece 1 at 21-DEC-16
channel ORA_DISK_1: finished piece 1 at 21-DEC-16
piece handle=/u01/app/oracle/fast_recovery_area/PROD1/backupset/2016_12_21/o1_mf_nnndf_TAG20161221T102837_d5mt6oxv_.bkp tag=TAG20161221T102837 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
Finished backup at 21-DEC-16

Starting Control File and SPFILE Autobackup at 21-DEC-16
piece handle=/u01/app/oracle/fast_recovery_area/PROD1/autobackup/2016_12_21/o1_mf_s_931170520_d5mt6s1z_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 21-DEC-16

9.再次向测试表t插入10记录，然后将EXAMPLE的数据文件删除
SYS@PROD1>create table scott.t(x int) tablespace EXAMPLE;

Table created.

SYS@PROD1>insert into scott.t select rownum from dual connect by rownum<=10;

10 rows created.

SYS@PROD1>commit;

Commit complete.

SYS@PROD1>select count(*) from scott.t;

COUNT(*)
----------
10

SYS@PROD1>select file_name from dba_data_files where tablespace_name='EXAMPLE';

FILE_NAME
--------------------------------------------------------------------------------
/u01/app/oracle/oradata/PROD1/example01.dbf

SYS@PROD1>! rm /u01/app/oracle/oradata/PROD1/example01.dbf

SYS@PROD1>! ls /u01/app/oracle/oradata/PROD1/example01.dbf
ls: /u01/app/oracle/oradata/PROD1/example01.dbf: No such file or directory

10.再次向测试表t插入10记录
此时，有些朋友可能觉得奇怪，表t所使用的表空间的数据文件已经丢失了，怎么数据写入成功了呢？
虽然我们的commit成功了，但dbwr进程实际上还没有工作（可以肯定的是，redo中一定记录了本次操作），
不过已经纳入到写入队列中，dbwr并不着急，在慢慢的处理已经提交且还没有写入磁盘的数据。

SYS@PROD1>insert into scott.t select rownum from dual connect by rownum<=10;

10 rows created.

SYS@PROD1>commit;

Commit complete.

11.手工触发一次检查点事件
SYS@PROD1>alter system checkpoint;

System altered.

12.因为之前利用RMAN备份过EXAMPLE表空间，我们可以使用RMAN进行恢复，将数据库启动到mount模式下
SYS@PROD1>shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.

SYS@PROD1>startup mount;
ORACLE instance started.

Total System Global Area 835104768 bytes
Fixed Size 2257840 bytes
Variable Size 520096848 bytes
Database Buffers 310378496 bytes
Redo Buffers 2371584 bytes
Database mounted.

RMAN> restore tablespace example;

Starting restore at 21-DEC-16
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=20 device type=DISK

channel ORA_DISK_1: starting datafile backup set restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_DISK_1: restoring datafile 00005 to /u01/app/oracle/oradata/PROD1/example01.dbf
channel ORA_DISK_1: reading from backup piece /u01/app/oracle/fast_recovery_area/PROD1/backupset/2016_12_21/o1_mf_nnndf_TAG20161221T102837_d5mt6oxv_.bkp
channel ORA_DISK_1: piece handle=/u01/app/oracle/fast_recovery_area/PROD1/backupset/2016_12_21/o1_mf_nnndf_TAG20161221T102837_d5mt6oxv_.bkp tag=TAG20161221T102837
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:07
Finished restore at 21-DEC-16

RMAN> recover tablespace example;

Starting recover at 21-DEC-16
using channel ORA_DISK_1

starting media recovery
media recovery complete, elapsed time: 00:00:01

Finished recover at 21-DEC-16

SYS@PROD1>alter database open;

Database altered.

验证
SYS@PROD1>select count(*) from scott.t;

COUNT(*)
----------
20

SYS@PROD1>! ls /u01/app/oracle/oradata/PROD1/example01.dbf
/u01/app/oracle/oradata/PROD1/example01.dbf

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