RMAN作为Oracle强大的备份恢复工具，可以协助我们恢复数据库到指定时间点，这便是Oracle不完全恢复的一种体现，通过这种方法可以找回我们曾经丢失的数据。这里以找回误TRUNCATE表数据为例给大家演示一下RMAN的不完全恢复功能。
1.调整数据库为归档模式
ora10g@secdb /home/oracle$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Wed Oct 19 22:10:38 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
sys@ora10g> archive log list;
Database log mode No Archive Mode
Automatic archival Disabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 73
Current log sequence 77
sys@ora10g> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
sys@ora10g> startup mount;
ORACLE instance started.
Total System Global Area 536870912 bytes
Fixed Size 1220460 bytes
Variable Size 318767252 bytes
Database Buffers 209715200 bytes
Redo Buffers 7168000 bytes
Database mounted.
sys@ora10g> alter database archivelog;
Database altered.
sys@ora10g> alter database open;
Database altered.
2.使用RMAN对数据库进行备份
1）备份数据库
ora10g@secdb /home/oracle$ rman target /
Recovery Manager: Release 10.2.0.1.0 - Production on Wed Oct 19 22:16:17 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
connected to target database: ORA10G (DBID=4067278754)
RMAN> backup database;
Starting backup at 20111019 22:16:35
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=214 devtype=DISK
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00010 name=/oracle/ora10gR2/oradata/ora10g/tbs_perf_01.dbf
input datafile fno=00003 name=/oracle/ora10gR2/oradata/ora10g/sysaux01.dbf
input datafile fno=00001 name=/oracle/ora10gR2/oradata/ora10g/system01.dbf
input datafile fno=00002 name=/oracle/ora10gR2/oradata/ora10g/undotbs01.dbf
input datafile fno=00005 name=/home/oracle/tbs_sec_d_01.dbf
input datafile fno=00004 name=/oracle/ora10gR2/oradata/ora10g/tbs_local_01.dbf
input datafile fno=00008 name=/oracle/ora10gR2/oradata/ora10g/tbs01.dbf
input datafile fno=00009 name=/oracle/ora10gR2/oradata/ora10g/tbs_secooler_01.dbf
input datafile fno=00016 name=/u01/app/oracle/oradata/PROD/disk1/INDX_01.dbf
input datafile fno=00017 name=/u01/app/oracle/oradata/PROD/disk1/TOOLS_01.dbf
input datafile fno=00007 name=/oracle/ora10gR2/oradata/ora10g/undotbs_guarantee.dbf
input datafile fno=00006 name=/oracle/ora10gR2/oradata/ora10g/users.dbf
channel ORA_DISK_1: starting piece 1 at 20111019 22:16:36
channel ORA_DISK_1: finished piece 1 at 20111019 22:17:41
piece handle=/oracle/ora10gR2/flash_recovery_area/ORA10G/backupset/2011_10_19/o1_mf_nnndf_TAG20111019T221636_79xpy532_.bkp tag=TAG20111019T221636 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:01:05
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00011 name=/u01/app/oracle/oradata/PROD/disk1/DATA01_01.dbf
input datafile fno=00012 name=/u01/app/oracle/oradata/PROD/disk2/DATA01_02.dbf
input datafile fno=00013 name=/u01/app/oracle/oradata/PROD/disk3/DATA01_03.dbf
input datafile fno=00014 name=/u01/app/oracle/oradata/PROD/disk4/DATA01_04.dbf
input datafile fno=00015 name=/u01/app/oracle/oradata/PROD/disk5/DATA01_05.dbf
channel ORA_DISK_1: starting piece 1 at 20111019 22:17:42
channel ORA_DISK_1: finished piece 1 at 20111019 22:17:45
piece handle=/oracle/ora10gR2/flash_recovery_area/ORA10G/backupset/2011_10_19/o1_mf_nnndf_TAG20111019T221636_79xq067w_.bkp tag=TAG20111019T221636 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
Finished backup at 20111019 22:17:45
Starting Control File and SPFILE Autobackup at 20111019 22:17:45
piece handle=/db_backup/rman_backup/c-4067278754-20111019-00 comment=NONE
Finished Control File and SPFILE Autobackup at 20111019 22:17:48
2）查看备份信息
RMAN> list backup;
List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ -----------------
48 Full 1.10G DISK 00:00:57 20111019 22:17:33
BP Key: 47 Status: AVAILABLE Compressed: NO Tag: TAG20111019T221636
Piece Name: /oracle/ora10gR2/flash_recovery_area/ORA10G/backupset/2011_10_19/o1_mf_nnndf_TAG20111019T221636_79xpy532_.bkp
List of Datafiles in backup set 48
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- ----------------- ----
1 Full 6494715 20111019 22:16:36 /oracle/ora10gR2/oradata/ora10g/system01.dbf
2 Full 6494715 20111019 22:16:36 /oracle/ora10gR2/oradata/ora10g/undotbs01.dbf
3 Full 6494715 20111019 22:16:36 /oracle/ora10gR2/oradata/ora10g/sysaux01.dbf
4 Full 6494715 20111019 22:16:36 /oracle/ora10gR2/oradata/ora10g/tbs_local_01.dbf
5 Full 6494715 20111019 22:16:36 /home/oracle/tbs_sec_d_01.dbf
6 Full 6494715 20111019 22:16:36 /oracle/ora10gR2/oradata/ora10g/users.dbf
7 Full 6494715 20111019 22:16:36 /oracle/ora10gR2/oradata/ora10g/undotbs_guarantee.dbf
8 Full 6494715 20111019 22:16:36 /oracle/ora10gR2/oradata/ora10g/tbs01.dbf
9 Full 6494715 20111019 22:16:36 /oracle/ora10gR2/oradata/ora10g/tbs_secooler_01.dbf
10 Full 6494715 20111019 22:16:36 /oracle/ora10gR2/oradata/ora10g/tbs_perf_01.dbf
16 Full 6494715 20111019 22:16:36 /u01/app/oracle/oradata/PROD/disk1/INDX_01.dbf
17 Full 6494715 20111019 22:16:36 /u01/app/oracle/oradata/PROD/disk1/TOOLS_01.dbf
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ -----------------
49 Full 1.02M DISK 00:00:01 20111019 22:17:43
BP Key: 48 Status: AVAILABLE Compressed: NO Tag: TAG20111019T221636
Piece Name: /oracle/ora10gR2/flash_recovery_area/ORA10G/backupset/2011_10_19/o1_mf_nnndf_TAG20111019T221636_79xq067w_.bkp
List of Datafiles in backup set 49
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- ----------------- ----
11 Full 6494738 20111019 22:17:42 /u01/app/oracle/oradata/PROD/disk1/DATA01_01.dbf
12 Full 6494738 20111019 22:17:42 /u01/app/oracle/oradata/PROD/disk2/DATA01_02.dbf
13 Full 6494738 20111019 22:17:42 /u01/app/oracle/oradata/PROD/disk3/DATA01_03.dbf
14 Full 6494738 20111019 22:17:42 /u01/app/oracle/oradata/PROD/disk4/DATA01_04.dbf
15 Full 6494738 20111019 22:17:42 /u01/app/oracle/oradata/PROD/disk5/DATA01_05.dbf
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ -----------------
50 Full 6.83M DISK 00:00:00 20111019 22:17:45
BP Key: 49 Status: AVAILABLE Compressed: NO Tag: TAG20111019T221745
Piece Name: /db_backup/rman_backup/c-4067278754-20111019-00
Control File Included: Ckp SCN: 6494743 Ckp time: 20111019 22:17:45
SPFILE Included: Modification time: 20111019 22:11:53
3.模拟数据库故障——表的误TRUNCATE
1）连接到数据库的sec用户
ora10g@secdb /home/oracle$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Wed Oct 19 22:20:57 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
sys@ora10g> conn sec/oracle_1
Connected.
2）查看T表中的数据行数
sec@ora10g> select count(*) from t;
COUNT(*)
----------
1000
此时T表中包含1000条数据。
3）查看当前时间，以便后续使用RMAN进行恢复
sec@ora10g> alter session set nls_date_format='yyyy-mm-dd hh34:mi:ss';
Session altered.
sec@ora10g> select sysdate from dual;
SYSDATE
-------------------
2011-10-19 22:21:38
4）这里模拟对T表的误删除（DDL类型的TRUNCATE方法）
sec@ora10g> truncate table t;
Table truncated.
sec@ora10g> select sysdate from dual;
SYSDATE
-------------------
2011-10-19 22:22:05
sec@ora10g> select count(*) from t;
COUNT(*)
----------
0
4.使用RMAN恢复到故障发生之前的时间点
我们这里恢复的时间点的目标是T表被删除之前的2011-10-19 22:21:38时刻。
【重要提醒】在使用RMAN完成基于时间点的不完全恢复之前，最好对现场做一个备份，我们这里只需要备份数据库的控制文件和日志文件即可。当恢复结束后不满足我们要求时，可以恢复控制文件和日志文件后重新进行恢复。
1）将数据库启动到mount状态
sec@ora10g> conn / as sysdba
Connected.
sys@ora10g> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
sys@ora10g> startup mount;
ORACLE instance started.
Total System Global Area 536870912 bytes
Fixed Size 1220460 bytes
Variable Size 318767252 bytes
Database Buffers 209715200 bytes
Redo Buffers 7168000 bytes
Database mounted.
2）使用RMAN脚本恢复数据库到指定时间点
（1）恢复脚本如下
run {
allocate channel c1 type disk;
allocate channel c2 type disk;
sql 'alter session set nls_date_format="yyyy-mm-dd hh34:mi:ss"';
set until time = '2011-10-19 22:21:38';
restore database;
recover database;
alter database open resetlogs;}
（2）恢复过程记录
RMAN> run {
2> allocate channel c1 type disk;
3> allocate channel c2 type disk;
4> sql 'alter session set nls_date_format="yyyy-mm-dd hh34:mi:ss"';
5> set until time = '2011-10-19 22:21:38';
6> restore database;
7> recover database;
8> alter database open resetlogs;}
using target database control file instead of recovery catalog
allocated channel: c1
channel c1: sid=211 devtype=DISK
allocated channel: c2
channel c2: sid=210 devtype=DISK
sql statement: alter session set nls_date_format="yyyy-mm-dd hh34:mi:ss"
executing command: SET until clause
Starting restore at 20111019 22:31:04
channel c1: starting datafile backupset restore
channel c1: specifying datafile(s) to restore from backup set
restoring datafile 00001 to /oracle/ora10gR2/oradata/ora10g/system01.dbf
restoring datafile 00002 to /oracle/ora10gR2/oradata/ora10g/undotbs01.dbf
restoring datafile 00003 to /oracle/ora10gR2/oradata/ora10g/sysaux01.dbf
restoring datafile 00004 to /oracle/ora10gR2/oradata/ora10g/tbs_local_01.dbf
restoring datafile 00005 to /home/oracle/tbs_sec_d_01.dbf
restoring datafile 00006 to /oracle/ora10gR2/oradata/ora10g/users.dbf
restoring datafile 00007 to /oracle/ora10gR2/oradata/ora10g/undotbs_guarantee.dbf
restoring datafile 00008 to /oracle/ora10gR2/oradata/ora10g/tbs01.dbf
restoring datafile 00009 to /oracle/ora10gR2/oradata/ora10g/tbs_secooler_01.dbf
restoring datafile 00010 to /oracle/ora10gR2/oradata/ora10g/tbs_perf_01.dbf
restoring datafile 00016 to /u01/app/oracle/oradata/PROD/disk1/INDX_01.dbf
restoring datafile 00017 to /u01/app/oracle/oradata/PROD/disk1/TOOLS_01.dbf
channel c1: reading from backup piece /oracle/ora10gR2/flash_recovery_area/ORA10G/backupset/2011_10_19/o1_mf_nnndf_TAG20111019T221636_79xpy532_.bkp
channel c2: starting datafile backupset restore
channel c2: specifying datafile(s) to restore from backup set
restoring datafile 00011 to /u01/app/oracle/oradata/PROD/disk1/DATA01_01.dbf
restoring datafile 00012 to /u01/app/oracle/oradata/PROD/disk2/DATA01_02.dbf
restoring datafile 00013 to /u01/app/oracle/oradata/PROD/disk3/DATA01_03.dbf
restoring datafile 00014 to /u01/app/oracle/oradata/PROD/disk4/DATA01_04.dbf
restoring datafile 00015 to /u01/app/oracle/oradata/PROD/disk5/DATA01_05.dbf
channel c2: reading from backup piece /oracle/ora10gR2/flash_recovery_area/ORA10G/backupset/2011_10_19/o1_mf_nnndf_TAG20111019T221636_79xq067w_.bkp
channel c2: restored backup piece 1
piece handle=/oracle/ora10gR2/flash_recovery_area/ORA10G/backupset/2011_10_19/o1_mf_nnndf_TAG20111019T221636_79xq067w_.bkp tag=TAG20111019T221636
channel c2: restore complete, elapsed time: 00:00:08
channel c1: restored backup piece 1
piece handle=/oracle/ora10gR2/flash_recovery_area/ORA10G/backupset/2011_10_19/o1_mf_nnndf_TAG20111019T221636_79xpy532_.bkp tag=TAG20111019T221636
channel c1: restore complete, elapsed time: 00:00:53
Finished restore at 20111019 22:31:58
Starting recover at 20111019 22:31:58
starting media recovery
media recovery complete, elapsed time: 00:00:01
Finished recover at 20111019 22:32:00
database opened
released channel: c1
released channel: c2
5.验证恢复成果
ora10g@secdb /home/oracle$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Wed Oct 19 22:35:37 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
sys@ora10g>
sys@ora10g>
sys@ora10g> conn sec/oracle_1
Connected.
sec@ora10g> select count(*) from t;
COUNT(*)
----------
1000
至此，曾经因TRUNCATE导致T表数据丢失的故障已被成功恢复。
6.小结
Oracle的RMAN工具非常强大，这里只是给出了不完全恢复的一个常见用法。在日常定制Oracle数据库备份恢复策略的时候RMAN是我们不可或缺的好帮手。
Good luck.
secooler
11.10.19
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