在Oracle數據庫中，對於用戶因DDL（drop或truncate）等誤操作，引起的數據丟失；一般可以通過基於數據庫的時間點不完全恢復和基於表空間的時間點恢復（TSPITR）進行數據恢復；但在Oracle 12c RMAN又推出了新的特性：基於表的時間點恢復，相比前兩種方式，更加方便和更具有可操作性。
案例分析：通過RMAN執行基於表時間點的恢復：
1、測試環境
11:56:54 SCOTT@ orcl> select * from tab
TNAME TABTYPE CLUSTERID
---------------------------------------- ------- ----------
T1 TABLE
SALGRADE TABLE
EMPLOYEES TABLE
EMP1 TABLE
EMP TABLE
DEPT TABLE
BONUS TABLE
7 rows selected.
11:56:54 SCOTT@ orcl>select count(1) from emp1;
COUNT(1)
----------
112
11:57:09 SCOTT@ orcl>select table_name,tablespace_name from user_tables;
TABLE_NAME TABLESPACE_NAME
------------------------------ ------------------------------
T1 USERS
EMP1 USERS
SALGRADE USERS
BONUS USERS
DEPT USERS
EMPLOYEES LOW_COST_TBS1
EMP LOW_COST_TBS1
7 rows selected.
2、查看數據庫備份信息
RMAN> list backup of database;
List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
3 Full 1.70M DISK 00:00:00 08-AUG-16
BP Key: 3 Status: AVAILABLE Compressed: NO Tag: TAG20160808T115958
Piece Name: /backup/orcl/ORCL_users_3.bk
List of Datafiles in backup set 3
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
6 Full 2874187 08-AUG-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_users_crgy2c5t_.dbf
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
4 Full 1.18G DISK 00:01:27 08-AUG-16
BP Key: 4 Status: AVAILABLE Compressed: NO Tag: TAG20160808T120909
Piece Name: /backup/orcl/ORCL_4.bak
List of Datafiles in backup set 4
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
1 Full 2875198 08-AUG-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_system_cr26h8nw_.dbf
2 Full 2875198 08-AUG-16 /u01/app/oracle/oradata/ORCL/datafile/adotbs1_01.dbf
3 Full 2875198 08-AUG-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_sysaux_cr26g2f6_.dbf
4 Full 2875198 08-AUG-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_undotbs1_cr26k3t7_.dbf
5 Full 2875198 08-AUG-16 /u01/app/oracle/oradata/ORCL/datafile/low_cost_tbs01.dbf
6 Full 2875198 08-AUG-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_users_crgy2c5t_.dbf
RMAN> list backup of tablespace users;
List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
3 Full 1.70M DISK 00:00:00 08-AUG-16
BP Key: 3 Status: AVAILABLE Compressed: NO Tag: TAG20160808T115958
Piece Name: /backup/orcl/ORCL_users_3.bk
List of Datafiles in backup set 3
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
6 Full 2874187 08-AUG-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_users_crgy2c5t_.dbf
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
4 Full 1.18G DISK 00:01:27 08-AUG-16
BP Key: 4 Status: AVAILABLE Compressed: NO Tag: TAG20160808T120909
Piece Name: /backup/orcl/ORCL_4.bak
List of Datafiles in backup set 4
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
6 Full 2875198 08-AUG-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_users_crgy2c5t_.dbf
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
6 Full 1.70M DISK 00:00:00 08-AUG-16
BP Key: 6 Status: AVAILABLE Compressed: NO Tag: TAG20160808T121206
Piece Name: /backup/orcl/ORCL_users_6.bk
List of Datafiles in backup set 6
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
6 Full 2875369 08-AUG-16 /u01/app/oracle/oradata/ORCL/datafile/o1_mf_users_crgy2c5t_.dbf
3、查看當前數據庫 scn
以此時間點或scn作爲表恢復的時間點（對於生產環境，需用logminer工具查詢準確的時間點，本案例爲測試環境）
12:13:02 SYS@ orcl>select timestamp_to_scn(current_timestamp) from v$database;
TIMESTAMP_TO_SCN(CURRENT_TIMESTAMP)
-----------------------------------
2875437
12:08:42 SCOTT@ orcl>select count(*) from emp1;
COUNT(*)
----------
112
4、SCOTT.EMP1被誤刪除
12:08:57 SCOTT@ orcl>drop table emp1 purge;
Table dropped.
5、通過rman執行表基於時間點的恢復操作
[oracle@enmoedu ~]$ mkdir /u01/aux
RMAN> recover table scott.emp1
2> until scn 2875437
3> auxiliary destination '/u01/aux';
Starting recover at 08-AUG-16
using target database control file instead of recovery catalog
current log archived
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=80 device type=DISK
RMAN-05026: WARNING: presuming following set of tablespaces applies to specified Point-in-Time
List of tablespaces expected to have UNDO segments
Tablespace SYSTEM
Tablespace UNDOTBS1
// Oracle自動建立用於恢復的auxiliary Instance
Creating automatic instance, with SID='fwsy'
initialization parameters used for automatic instance:
db_name=ORCL
db_unique_name=fwsy_pitr_ORCL
compatible=12.1.0.2.0
db_block_size=8192
db_files=200
diagnostic_dest=/u01/app/oracle
_system_trig_enabled=FALSE
sga_target=564M
processes=200
db_create_file_dest=/u01/aux
log_archive_dest_1='location=/u01/aux'
#No auxiliary parameter file used
starting up automatic instance ORCL
Oracle instance started
Total System Global Area 591396864 bytes
Fixed Size 2927096 bytes
Variable Size 176162312 bytes
Database Buffers 406847488 bytes
Redo Buffers 5459968 bytes
Automatic instance created
//通過源庫的rman備份，restore數據庫到auxiliary database
contents of Memory Script:
{
# set requested point in time
set until scn 2875437;
# restore the controlfile
restore clone controlfile;
# mount the controlfile
sql clone 'alter database mount clone database';
# archive current online log
sql 'alter system archive log current';
}
executing Memory Script
executing command: SET until clause
Starting restore at 08-AUG-16
allocated channel: ORA_AUX_DISK_1
channel ORA_AUX_DISK_1: SID=21 device type=DISK
channel ORA_AUX_DISK_1: starting datafile backup set restore
channel ORA_AUX_DISK_1: restoring control file
channel ORA_AUX_DISK_1: reading from backup piece /backup/orcl/ORCL_5.bak
channel ORA_AUX_DISK_1: piece handle=/backup/orcl/ORCL_5.bak tag=TAG20160808T120909
channel ORA_AUX_DISK_1: restored backup piece 1
channel ORA_AUX_DISK_1: restore complete, elapsed time: 00:00:01
output file name=/u01/aux/ORCL/controlfile/o1_mf_ctj1v7x9_.ctl
Finished restore at 08-AUG-16
sql statement: alter database mount clone database
sql statement: alter system archive log current
contents of Memory Script:
{
# set requested point in time
set until scn 2875437;
// restore的表空間有system、sysaux、undo、users（表所在的表空間）
# set destinations for recovery set and auxiliary set datafiles
set newname for clone datafile 1 to new;
set newname for clone datafile 4 to new;
set newname for clone datafile 3 to new;
set newname for clone tempfile 1 to new;
# switch all tempfiles
switch clone tempfile all;
# restore the tablespaces in the recovery set and the auxiliary set
restore clone datafile 1, 4, 3;
switch clone datafile all;
}
executing Memory Script
executing command: SET until clause
executing command: SET NEWNAME
executing command: SET NEWNAME
executing command: SET NEWNAME
executing command: SET NEWNAME
renamed tempfile 1 to /u01/aux/ORCL/datafile/o1_mf_temp_%u_.tmp in control file
Starting restore at 08-AUG-16
using channel ORA_AUX_DISK_1
channel ORA_AUX_DISK_1: starting datafile backup set restore
channel ORA_AUX_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_AUX_DISK_1: restoring datafile 00001 to /u01/aux/ORCL/datafile/o1_mf_system_%u_.dbf
channel ORA_AUX_DISK_1: restoring datafile 00004 to /u01/aux/ORCL/datafile/o1_mf_undotbs1_%u_.dbf
channel ORA_AUX_DISK_1: restoring datafile 00003 to /u01/aux/ORCL/datafile/o1_mf_sysaux_%u_.dbf
channel ORA_AUX_DISK_1: reading from backup piece /backup/orcl/ORCL_4.bak
channel ORA_AUX_DISK_1: piece handle=/backup/orcl/ORCL_4.bak tag=TAG20160808T120909
channel ORA_AUX_DISK_1: restored backup piece 1
channel ORA_AUX_DISK_1: restore complete, elapsed time: 00:01:05
Finished restore at 08-AUG-16
datafile 1 switched to datafile copy
input datafile copy RECID=4 STAMP=919340207 file name=/u01/aux/ORCL/datafile/o1_mf_system_ctj1vgr5_.dbf
datafile 4 switched to datafile copy
input datafile copy RECID=5 STAMP=919340207 file name=/u01/aux/ORCL/datafile/o1_mf_undotbs1_ctj1vgsj_.dbf
datafile 3 switched to datafile copy
input datafile copy RECID=6 STAMP=919340208 file name=/u01/aux/ORCL/datafile/o1_mf_sysaux_ctj1vgr8_.dbf
contents of Memory Script:
{
# set requested point in time
set until scn 2875437;
# online the datafiles restored or switched
sql clone "alter database datafile 1 online";
sql clone "alter database datafile 4 online";
sql clone "alter database datafile 3 online";
# recover and open database read only
recover clone database tablespace "SYSTEM", "UNDOTBS1", "SYSAUX";
sql clone 'alter database open read only';
}
executing Memory Script
executing command: SET until clause
sql statement: alter database datafile 1 online
sql statement: alter database datafile 4 online
sql statement: alter database datafile 3 online
// 在auxiliary database執行基於時間點的不完全恢復
Starting recover at 08-AUG-16
using channel ORA_AUX_DISK_1
starting media recovery
archived log for thread 1 with sequence 22 is already on disk as file /dsk1/arch_orcl/arch__1_22_916789058.log
archived log file name=/dsk1/arch_orcl/arch__1_22_916789058.log thread=1 sequence=22
media recovery complete, elapsed time: 00:00:01
Finished recover at 08-AUG-16
sql statement: alter database open read only
contents of Memory Script:
{
sql clone "create spfile from memory";
shutdown clone immediate;
startup clone nomount;
sql clone "alter system set control_files =
''/u01/aux/ORCL/controlfile/o1_mf_ctj1v7x9_.ctl'' comment=
''RMAN set'' scope=spfile";
shutdown clone immediate;
startup clone nomount;
# mount database
sql clone 'alter database mount clone database';
}
executing Memory Script
sql statement: create spfile from memory
database closed
database dismounted
Oracle instance shut down
connected to auxiliary database (not started)
Oracle instance started
Total System Global Area 591396864 bytes
Fixed Size 2927096 bytes
Variable Size 180356616 bytes
Database Buffers 402653184 bytes
Redo Buffers 5459968 bytes
sql statement: alter system set control_files = ''/u01/aux/ORCL/controlfile/o1_mf_ctj1v7x9_.ctl'' comment= ''RMAN set'' scope=spfile
Oracle instance shut down
connected to auxiliary database (not started)
Oracle instance started
Total System Global Area 591396864 bytes
Fixed Size 2927096 bytes
Variable Size 180356616 bytes
Database Buffers 402653184 bytes
Redo Buffers 5459968 bytes
sql statement: alter database mount clone database
contents of Memory Script:
{
# set requested point in time
set until scn 2875437;
# set destinations for recovery set and auxiliary set datafiles
set newname for datafile 6 to new;
# restore the tablespaces in the recovery set and the auxiliary set
restore clone datafile 6;
switch clone datafile all;
}
executing Memory Script
executing command: SET until clause
executing command: SET NEWNAME
Starting restore at 08-AUG-16
allocated channel: ORA_AUX_DISK_1
channel ORA_AUX_DISK_1: SID=21 device type=DISK
channel ORA_AUX_DISK_1: starting datafile backup set restore
channel ORA_AUX_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_AUX_DISK_1: restoring datafile 00006 to /u01/aux/FWSY_PITR_ORCL/datafile/o1_mf_users_%u_.dbf
channel ORA_AUX_DISK_1: reading from backup piece /backup/orcl/ORCL_users_6.bk
channel ORA_AUX_DISK_1: piece handle=/backup/orcl/ORCL_users_6.bk tag=TAG20160808T121206
channel ORA_AUX_DISK_1: restored backup piece 1
channel ORA_AUX_DISK_1: restore complete, elapsed time: 00:00:01
Finished restore at 08-AUG-16
datafile 6 switched to datafile copy
input datafile copy RECID=8 STAMP=919340265 file name=/u01/aux/FWSY_PITR_ORCL/datafile/o1_mf_users_ctj1z8gv_.dbf
contents of Memory Script:
{
# set requested point in time
set until scn 2875437;
# online the datafiles restored or switched
sql clone "alter database datafile 6 online";
# recover and open resetlogs
recover clone database tablespace "USERS", "SYSTEM", "UNDOTBS1", "SYSAUX" delete archivelog;
alter clone database open resetlogs;
}
executing Memory Script
executing command: SET until clause
sql statement: alter database datafile 6 online
Starting recover at 08-AUG-16
using channel ORA_AUX_DISK_1
starting media recovery
archived log for thread 1 with sequence 22 is already on disk as file /dsk1/arch_orcl/arch__1_22_916789058.log
archived log file name=/dsk1/arch_orcl/arch__1_22_916789058.log thread=1 sequence=22
media recovery complete, elapsed time: 00:00:00
Finished recover at 08-AUG-16
database opened
contents of Memory Script:
{
# create directory for datapump import
sql "create or replace directory TSPITR_DIROBJ_DPDIR as ''
/u01/aux''";
# create directory for datapump export
sql clone "create or replace directory TSPITR_DIROBJ_DPDIR as ''
/u01/aux''";
}
executing Memory Script
sql statement: create or replace directory TSPITR_DIROBJ_DPDIR as ''/u01/aux''
sql statement: create or replace directory TSPITR_DIROBJ_DPDIR as ''/u01/aux''
//在auxiliary database執行表（被刪除表）的導出
Performing export of tables...
EXPDP> Starting "SYS"."TSPITR_EXP_fwsy_zBEo":
EXPDP> Estimate in progress using BLOCKS method...
EXPDP> Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
EXPDP> Total estimation using BLOCKS method: 64 KB
EXPDP> Processing object type TABLE_EXPORT/TABLE/TABLE
EXPDP> Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
EXPDP> Processing object type TABLE_EXPORT/TABLE/STATISTICS/MARKER
EXPDP> . . exported "SCOTT"."EMP1" 12.74 KB 112 rows
EXPDP> Master table "SYS"."TSPITR_EXP_fwsy_zBEo" successfully loaded/unloaded
EXPDP> ******************************************************************************
EXPDP> Dump file set for SYS.TSPITR_EXP_fwsy_zBEo is:
EXPDP> /u01/aux/tspitr_fwsy_78303.dmp
EXPDP> Job "SYS"."TSPITR_EXP_fwsy_zBEo" successfully completed at Mon Aug 8 12:19:02 2016 elapsed 0 00:00:32
Export completed
contents of Memory Script:
{
# shutdown clone before import
shutdown clone abort
}
executing Memory Script
Oracle instance shut down
//在源庫上執行表的導入
Performing import of tables...
IMPDP> Master table "SYS"."TSPITR_IMP_fwsy_FAoe" successfully loaded/unloaded
IMPDP> Starting "SYS"."TSPITR_IMP_fwsy_FAoe":
IMPDP> Processing object type TABLE_EXPORT/TABLE/TABLE
IMPDP> Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
IMPDP> . . imported "SCOTT"."EMP1" 12.74 KB 112 rows
IMPDP> Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
IMPDP> Processing object type TABLE_EXPORT/TABLE/STATISTICS/MARKER
IMPDP> Job "SYS"."TSPITR_IMP_fwsy_FAoe" successfully completed at Mon Aug 8 12:19:38 2016 elapsed 0 00:00:25
Import completed
//自動刪除auxiliary Instance
Removing automatic instance
Automatic instance removed
auxiliary instance file /u01/aux/ORCL/datafile/o1_mf_temp_ctj1xmxr_.tmp deleted
auxiliary instance file /u01/aux/FWSY_PITR_ORCL/onlinelog/o1_mf_3_ctj1zdb8_.log deleted
auxiliary instance file /u01/aux/FWSY_PITR_ORCL/onlinelog/o1_mf_2_ctj1zc8f_.log deleted
auxiliary instance file /u01/aux/FWSY_PITR_ORCL/onlinelog/o1_mf_1_ctj1zb00_.log deleted
auxiliary instance file /u01/aux/FWSY_PITR_ORCL/datafile/o1_mf_users_ctj1z8gv_.dbf deleted
auxiliary instance file /u01/aux/ORCL/datafile/o1_mf_sysaux_ctj1vgr8_.dbf deleted
auxiliary instance file /u01/aux/ORCL/datafile/o1_mf_undotbs1_ctj1vgsj_.dbf deleted
auxiliary instance file /u01/aux/ORCL/datafile/o1_mf_system_ctj1vgr5_.dbf deleted
auxiliary instance file /u01/aux/ORCL/controlfile/o1_mf_ctj1v7x9_.ctl deleted
auxiliary instance file tspitr_fwsy_78303.dmp deleted
Finished recover at 08-AUG-16
---恢復完成！
6、查詢恢復表數據
RMAN> select count(*) from scott.emp1;
COUNT(*)
----------
112
12:21:05 SCOTT@ orcl>select count(*) from emp1;
COUNT(*)
----------
112
---------- 至此，通過基於表的時間點恢復，可以很方便的恢復用於DDL（drop、truncate）等誤操作，比起基於表空間的時間點恢復（TSPITR）更具與可操作性。