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Oracle12 RMAN新特性Recover Table有什么作用

發(fā)布時間：2021-11-09 14:45:01 來源：億速云 閱讀：108 作者：iii 欄目：關系型數據庫

這篇文章主要講解了“ Oracle12 RMAN新特性Recover Table有什么作用”，文中的講解內容簡單清晰，易于學習與理解，下面請大家跟著小編的思路慢慢深入，一起來研究和學習“ Oracle12 RMAN新特性Recover Table有什么作用”吧！

在 Oracle 12c 之前，如果誤刪一張表，常規(guī)的方法是 Flashback 閃回或 TSPITR。而開啟 flashback 會消耗磁盤空間，且如果被 purge 或者經過 DDL，將無法 flashback。如果需要恢復的表空間過大，TSPITR 會耗時非常久。12c 中提供了Table Recovery 的新特性，可以針對單表（或單個表分區(qū)）基于時間點進行恢復，該特性用以直接從 RMAN 備份中恢復表的方法，該特性有以下特點：

  • 不影響數據庫中的其他數據庫對象

  • 減少時間和磁盤空間的消耗，和早期的 TSPIRT 工作流程類似

  • 從另一個磁盤路徑恢復表空間

  • 導出想要的表數據

  • 導入到原數據庫（可選）

 recover table 可以將一個或多個表或表分區(qū)恢復到指定的時間點，而不會影響其余的數據庫對象?？梢允褂靡郧皠?chuàng)建的 RMAN 備份將表和表分區(qū)恢復到指定的時間點。

該表被恢復到一個輔助實例中，并且可以選擇：

  • 使用 REMAP 選項將恢復的表導入新表或分區(qū)

  • 僅在恢復的表中創(chuàng)建 expdp dump 文件，以便在其他時間進行導入

 先決條件

目標數據庫必須處于讀寫模式。

目標數據庫必須處于 ARCHIVELOG 模式。

您必須擁有表或表分區(qū)的 RMAN 備份，因為它們存在于要恢復這些對象的時間點。

要恢復單個表分區(qū)，目標數據庫的 COMPATIBLE 初始化參數必須設置為 11.1.0 或更高。

請確保 AUXILIARY DESTINATION 有足夠的空間來恢復 system、sysaux、undo 以及恢復表所需的表空間。

請注意，表恢復后，輔助目標中的這些文件將自動刪除

必須使用 AUXILIARY DESTINATION 子句和后面其中一個子句來指定恢復的時間點：UNTIL TIME、UNTIL SCN 或 UNTIL SEQUENCE。

 使用限制

  •  屬于SYS模式的表和表分區(qū)無法恢復。

  •  SYSTEM和SYSAUX表空間中的表和表分區(qū)無法恢復。

  •  standby數據庫上的表和表分區(qū)無法恢復。

  •  命名為NOT NULL約束的表不能用REMAP選項恢復。



RMAN從備份中自動處理恢復表或者表分區(qū)時會執(zhí)行如下步驟：

1.判斷哪些備份包含需要恢復的表或表分區(qū)，然后根據指定的時間來進行恢復。

2.判斷目標主機上是否有足夠的空間來創(chuàng)建auxiliary instance，該實例用于處理表或分區(qū)的恢復。 如果需要的空間不足，那么RMAN 會報錯并退出恢復操作。

3.創(chuàng)建auxiliary database，并根據指定的時間來恢復指定的表或表分區(qū)到auxiliary database中。 輔助數據庫的數據文件位置可以在命令中指定。

4.創(chuàng)建包含恢復表或表分區(qū)的數據泵文件（expdp dump file）。 數據泵的名稱和位置也可以在命令中指定。

5. （可選操作）將上一步生產的數據泵文件導入到目標實例中。當然也可以選擇不導入，如果選擇不導入就必須使用impdp 手工導入。

6. （可選操作）在目標數據庫中rename 恢復表或表分區(qū)。

使用場景

RMAN 的表級和表分區(qū)級恢復在以下場景中非常適用：

（1） 需要將非常少量的表恢復至特定的時間點。在這種情況下，TSPITR 不是最有效的解決方案，因為它會將表空間中的所有對象恢復到指定的時間點。

（2） 需要恢復已被邏輯損壞或已被 drop 和 purge 的表。

（3） flashback 不可用，比如需要的 undo 數據被覆蓋。

（4） DDL 操作修改表結構后丟失的數據。flashback table 不能跨越 DDL（例如truncate）來回滾表。

在這Recover table 過程演示

創(chuàng)建測試表

SQL> create table t_recover_test as select * from dba_objects;  

 

Table created.

 

SQL> select count(*) from t_recover_test;

 

COUNT(*)

----------

 72652

備份

[oracle@localhost ~]$ rman target /

Recovery Manager: Release 12.2.0.1.0 - Production on Thu Jun 28 21:06:17 2018

Copyright (c) 1982, 2017, Oracle and/or its affiliates.  All rights reserved.

connected to target database: PCC (DBID=3164878903)

RMAN> backup database format '/home/oracle/bak/db_%U';

 

Starting backup at 28-JUN-18

using target database control file instead of recovery catalog

allocated channel: ORA_DISK_1

channel ORA_DISK_1: SID=61 device type=DISK

channel ORA_DISK_1: starting full datafile backup set

channel ORA_DISK_1: specifying datafile(s) in backup set

input datafile file number=00001 name=/home/oracle/oradata/pcc/system01.dbf

input datafile file number=00003 name=/home/oracle/oradata/pcc/sysaux01.dbf

input datafile file number=00004 name=/home/oracle/oradata/pcc/undotbs01.dbf

input datafile file number=00005 name=/home/oracle/oradata/pcc/tbs_zyq01.dbf

input datafile file number=00007 name=/home/oracle/oradata/pcc/users01.dbf

channel ORA_DISK_1: starting piece 1 at 28-JUN-18

channel ORA_DISK_1: finished piece 1 at 28-JUN-18

piece handle=/home/oracle/bak/db_01t6k254_1_1 tag=TAG20180628T215236 comment=NONE

channel ORA_DISK_1: backup set complete, elapsed time: 00:00:15

Finished backup at 28-JUN-18

 

Starting Control File and SPFILE Autobackup at 28-JUN-18

piece handle=/u01/app/oracle/product/12.2.0.1/dbs/c-3164878903-20180628-00 comment=NONE

Finished Control File and SPFILE Autobackup at 28-JUN-18

恢復表

[oracle@localhost ~]$ rman target /

Recovery Manager: Release 12.2.0.1.0 - Production on Fri Jun 29 00:52:29 2018

Copyright (c) 1982, 2017, Oracle and/or its affiliates.  All rights reserved.

connected to target database: PCC (DBID=3164878903)

RMAN> RECOVER TABLE zyq.t_recover_test

until time  "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh34:mi:ss')"

AUXILIARY DESTINATION '/data01'

REMAP TABLE zyq.t_recover_test:t_recover_test_map;

 

Starting recover at 29-JUN-18

using target database control file instead of recovery catalog

allocated channel: ORA_DISK_1

channel ORA_DISK_1: SID=66 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

 

Creating automatic instance, with SID='hCed'


initialization parameters used for automatic instance:

db_name=PCC

db_unique_name=hCed_pitr_PCC

compatible=12.2.0

db_block_size=8192

db_files=200

diagnostic_dest=/u01/app/oracle

_system_trig_enabled=FALSE

sga_target=732M

processes=200

db_create_file_dest=/data01

log_archive_dest_1='location=/data01'

#No auxiliary parameter file used


starting up automatic instance PCC

 

Oracle instance started

 

Total System Global Area     767557632 bytes

 

Fixed Size                     8625416 bytes

Variable Size                213910264 bytes

Database Buffers             541065216 bytes

Redo Buffers                   3956736 bytes

Automatic instance created

 

contents of Memory Script:

{

# set requested point in time

set until  time "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh34:mi:ss')";

# 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 29-JUN-18

allocated channel: ORA_AUX_DISK_1

channel ORA_AUX_DISK_1: SID=35 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 /u01/app/oracle/product/12.2.0.1/dbs/c-3164878903-20180628-01

channel ORA_AUX_DISK_1: piece handle=/u01/app/oracle/product/12.2.0.1/dbs/c-3164878903-20180628-01 tag=TAG20180628T234914

channel ORA_AUX_DISK_1: restored backup piece 1

channel ORA_AUX_DISK_1: restore complete, elapsed time: 00:00:02

output file name=/data01/PCC/controlfile/o1_mf_fmcsc00p_.ctl

Finished restore at 29-JUN-18

 

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  time "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh34:mi:ss')";

# 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 /data01/PCC/datafile/o1_mf_temp_%u_.tmp in control file

 

Starting restore at 29-JUN-18

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 /data01/PCC/datafile/o1_mf_system_%u_.dbf

channel ORA_AUX_DISK_1: restoring datafile 00004 to /data01/PCC/datafile/o1_mf_undotbs1_%u_.dbf

channel ORA_AUX_DISK_1: restoring datafile 00003 to /data01/PCC/datafile/o1_mf_sysaux_%u_.dbf

channel ORA_AUX_DISK_1: reading from backup piece /home/oracle/bak/db_01t6k254_1_1

channel ORA_AUX_DISK_1: piece handle=/home/oracle/bak/db_01t6k254_1_1 tag=TAG20180628T215236

channel ORA_AUX_DISK_1: restored backup piece 1

channel ORA_AUX_DISK_1: restore complete, elapsed time: 00:00:15

Finished restore at 29-JUN-18

 

datafile 1 switched to datafile copy

input datafile copy RECID=4 STAMP=980038406 file name=/data01/PCC/datafile/o1_mf_system_fmcsc755_.dbf

datafile 4 switched to datafile copy

input datafile copy RECID=5 STAMP=980038406 file name=/data01/PCC/datafile/o1_mf_undotbs1_fmcsc75h_.dbf

datafile 3 switched to datafile copy

input datafile copy RECID=6 STAMP=980038406 file name=/data01/PCC/datafile/o1_mf_sysaux_fmcsc75c_.dbf

 

contents of Memory Script:

{

# set requested point in time

set until  time "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh34:mi:ss')";

# 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

 

Starting recover at 29-JUN-18

using channel ORA_AUX_DISK_1

 

starting media recovery

 

archived log for thread 1 with sequence 3 is already on disk as file /u01/app/oracle/product/12.2.0.1/dbs/arch2_3_979872889.dbf

archived log for thread 1 with sequence 4 is already on disk as file /u01/app/oracle/product/12.2.0.1/dbs/arch2_4_979872889.dbf

archived log file name=/u01/app/oracle/product/12.2.0.1/dbs/arch2_3_979872889.dbf thread=1 sequence=3

archived log file name=/u01/app/oracle/product/12.2.0.1/dbs/arch2_4_979872889.dbf thread=1 sequence=4

media recovery complete, elapsed time: 00:00:11

Finished recover at 29-JUN-18

 

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 =

''/data01/PCC/controlfile/o1_mf_fmcsc00p_.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     767557632 bytes

 

Fixed Size                     8625416 bytes

Variable Size                213910264 bytes

Database Buffers             541065216 bytes

Redo Buffers                   3956736 bytes

 

sql statement: alter system set  control_files =   ''/data01/PCC/controlfile/o1_mf_fmcsc00p_.ctl'' comment= ''RMAN set'' scope=spfile

 

Oracle instance shut down

 

connected to auxiliary database (not started)

Oracle instance started

 

Total System Global Area     767557632 bytes

 

Fixed Size                     8625416 bytes

Variable Size                213910264 bytes

Database Buffers             541065216 bytes

Redo Buffers                   3956736 bytes

 

sql statement: alter database mount clone database

 

contents of Memory Script:

{

# set requested point in time

set until  time "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh34:mi:ss')";

# set destinations for recovery set and auxiliary set datafiles

set newname for datafile  5 to new;

# restore the tablespaces in the recovery set and the auxiliary set

restore clone datafile  5;

 

switch clone datafile all;

}

executing Memory Script

 

executing command: SET until clause

 

executing command: SET NEWNAME

 

Starting restore at 29-JUN-18

allocated channel: ORA_AUX_DISK_1

channel ORA_AUX_DISK_1: SID=34 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 00005 to /data01/HCED_PITR_PCC/datafile/o1_mf_tbs_zyq_%u_.dbf

channel ORA_AUX_DISK_1: reading from backup piece /home/oracle/bak/db_01t6k254_1_1

channel ORA_AUX_DISK_1: piece handle=/home/oracle/bak/db_01t6k254_1_1 tag=TAG20180628T215236

channel ORA_AUX_DISK_1: restored backup piece 1

channel ORA_AUX_DISK_1: restore complete, elapsed time: 00:00:03

Finished restore at 29-JUN-18

 

datafile 5 switched to datafile copy

input datafile copy RECID=8 STAMP=980038478 file name=/data01/HCED_PITR_PCC/datafile/o1_mf_tbs_zyq_fmcsfttn_.dbf

 

contents of Memory Script:

{

# set requested point in time

set until  time "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh34:mi:ss')";

# online the datafiles restored or switched

sql clone "alter database datafile  5 online";

# recover and open resetlogs

recover clone database tablespace  "TBS_ZYQ", "SYSTEM", "UNDOTBS1", "SYSAUX" delete archivelog;

alter clone database open resetlogs;

}

executing Memory Script

 

executing command: SET until clause

 

sql statement: alter database datafile  5 online

 

Starting recover at 29-JUN-18

using channel ORA_AUX_DISK_1

 

starting media recovery

 

archived log for thread 1 with sequence 3 is already on disk as file /u01/app/oracle/product/12.2.0.1/dbs/arch2_3_979872889.dbf

archived log for thread 1 with sequence 4 is already on disk as file /u01/app/oracle/product/12.2.0.1/dbs/arch2_4_979872889.dbf

archived log file name=/u01/app/oracle/product/12.2.0.1/dbs/arch2_3_979872889.dbf thread=1 sequence=3

archived log file name=/u01/app/oracle/product/12.2.0.1/dbs/arch2_4_979872889.dbf thread=1 sequence=4

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

Finished recover at 29-JUN-18

 

database opened

 

contents of Memory Script:

{

# create directory for datapump import

sql "create or replace directory TSPITR_DIROBJ_DPDIR as ''

/data01''";

# create directory for datapump export

sql clone "create or replace directory TSPITR_DIROBJ_DPDIR as ''

/data01''";

}

executing Memory Script

 

sql statement: create or replace directory TSPITR_DIROBJ_DPDIR as ''/data01''

 

sql statement: create or replace directory TSPITR_DIROBJ_DPDIR as ''/data01''

 

Performing export of tables...

   EXPDP> Starting "SYS"."TSPITR_EXP_hCed_Dhxe":  

   EXPDP> Processing object type TABLE_EXPORT/TABLE/TABLE_DATA

   EXPDP> Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS

   EXPDP> Processing object type TABLE_EXPORT/TABLE/STATISTICS/MARKER

   EXPDP> Processing object type TABLE_EXPORT/TABLE/TABLE

   EXPDP> . . exported "ZYQ"."T_RECOVER_TEST"                      9.324 MB   72652 rows

   EXPDP> Master table "SYS"."TSPITR_EXP_hCed_Dhxe" successfully loaded/unloaded

   EXPDP> ******************************************************************************

   EXPDP> Dump file set for SYS.TSPITR_EXP_hCed_Dhxe is:

   EXPDP>   /data01/tspitr_hCed_71393.dmp

   EXPDP> Job "SYS"."TSPITR_EXP_hCed_Dhxe" successfully completed at Fri Jun 29 00:55:41 2018 elapsed 0 00:00:35

Export completed

 

contents of Memory Script:

{

# shutdown clone before import

shutdown clone abort

}

executing Memory Script

 

Oracle instance shut down

 

Performing import of tables...

   IMPDP> Master table "SYS"."TSPITR_IMP_hCed_Arhm" successfully loaded/unloaded

   IMPDP> Starting "SYS"."TSPITR_IMP_hCed_Arhm":  

   IMPDP> Processing object type TABLE_EXPORT/TABLE/TABLE

   IMPDP> Processing object type TABLE_EXPORT/TABLE/TABLE_DATA

   IMPDP> . . imported "ZYQ"."T_RECOVER_TEST_MAP"                  9.324 MB   72652 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_hCed_Arhm" successfully completed at Fri Jun 29 00:56:43 2018 elapsed 0 00:00:45

Import completed

 

Removing automatic instance

Automatic instance removed

auxiliary instance file /data01/PCC/datafile/o1_mf_temp_fmcsd5ny_.tmp deleted

auxiliary instance file /data01/HCED_PITR_PCC/onlinelog/o1_mf_3_fmcsg3y6_.log deleted

auxiliary instance file /data01/HCED_PITR_PCC/onlinelog/o1_mf_2_fmcsg07o_.log deleted

auxiliary instance file /data01/HCED_PITR_PCC/onlinelog/o1_mf_1_fmcsfzr1_.log deleted

auxiliary instance file /data01/HCED_PITR_PCC/datafile/o1_mf_tbs_zyq_fmcsfttn_.dbf deleted

auxiliary instance file /data01/PCC/datafile/o1_mf_sysaux_fmcsc75c_.dbf deleted

auxiliary instance file /data01/PCC/datafile/o1_mf_undotbs1_fmcsc75h_.dbf deleted

auxiliary instance file /data01/PCC/datafile/o1_mf_system_fmcsc755_.dbf deleted

auxiliary instance file /data01/PCC/controlfile/o1_mf_fmcsc00p_.ctl deleted

auxiliary instance file tspitr_hCed_71393.dmp deleted

Finished recover at 29-JUN-18

 

RMAN>

驗證

SQL> select count(*) from T_RECOVER_TEST_MAP;

 

  COUNT(*)

----------

     72652

感謝各位的閱讀，以上就是“ Oracle12 RMAN新特性Recover Table有什么作用”的內容了，經過本文的學習后，相信大家對 Oracle12 RMAN新特性Recover Table有什么作用這一問題有了更深刻的體會，具體使用情況還需要大家實踐驗證。這里是億速云，小編將為大家推送更多相關知識點的文章，歡迎關注！

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