Oracle 12c RMAN新特性之Recover Table
1. 介绍
1.1 概述
在Oracle 12c之前，如果误删一张表，常规的方法是Flashback闪回或TSPITR。而开启flashback会消耗磁盘空间，且如果被purge或者经过DDL，将无法flashback。如果需要恢复的表空间过大，TSPITR会耗时非常久。12c中提供了Table Recovery的新特性，可以针对单表（或单个表分区）基于时间点进行恢复，该特性用以直接从RMAN 备份中恢复表的方法，该特性有以下特点：
不影响数据库中的其他数据库对象
减少时间和磁盘空间的消耗，和早期的TSPIRT工作流程类似
从另一个磁盘路径恢复表空间
导出想要的表数据
导入到原数据库（可选）
recover table可以将一个或多个表或表分区恢复到指定的时间点，而不会影响其余的数据库对象。可以使用以前创建的RMAN备份将表和表分区恢复到指定的时间点。
该表被恢复到一个辅助实例中，并且可以选择：
（1） 使用REMAP选项将恢复的表导入新表或分区
（2） 仅在恢复的表中创建expdp dump文件，以便在其他时间进行导入
1.2 先决条件：
目标数据库必须处于读写模式。
目标数据库必须处于ARCHIVELOG模式。
您必须拥有表或表分区的RMAN备份，因为它们存在于要恢复这些对象的时间点。
要恢复单个表分区，目标数据库的COMPATIBLE初始化参数必须设置为11.1.0或更高。
请确保AUXILIARY DESTINATION有足够的空间来恢复system、sysaux、undo以及恢复表所需的表空间。
请注意，表恢复后，辅助目标中的这些文件将自动删除
必须使用AUXILIARY DESTINATION子句和后面其中一个子句来指定恢复的时间点：UNTIL TIME、UNTIL SCN或UNTIL SEQUENCE。
1.3 使用限制：
（1） 属于SYS模式的表和表分区无法恢复。
（2） SYSTEM和SYSAUX表空间中的表和表分区无法恢复。
（3） standby数据库上的表和表分区无法恢复。
（4） 命名为NOT NULL约束的表不能用REMAP选项恢复。
2. 使用场景
RMAN的表级和表分区级恢复在以下场景中非常适用：
（1） 需要将非常少量的表恢复至特定的时间点。在这种情况下，TSPITR不是最有效的解决方案，因为它会将表空间中的所有对象恢复到指定的时间点。
（2） 需要恢复已被逻辑损坏或已被drop和purge的表。
（3） flashback不可用，比如需要的undo数据被覆盖。
（4） DDL操作修改表结构后丢失的数据。flashback table不能跨越DDL（例如truncate）来回滚表。
3. Recover table过程演示
2.1 创建测试表
SQL> create table t_recover_test as select * from dba_objects; Table created. SQL> select count(*) from t_recover_test;COUNT(*)---------- 726522.2 备份
[oracle@localhost ~]$ rman target /Recovery Manager: Release 12.2.0.1.0 - Production on Thu Jun 28 21:06:17 2018Copyright (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-18using target database control file instead of recovery catalogallocated channel: ORA_DISK_1channel ORA_DISK_1: SID=61 device type=DISKchannel ORA_DISK_1: starting full datafile backup setchannel ORA_DISK_1: specifying datafile(s) in backup setinput datafile file number=00001 name=/home/oracle/oradata/pcc/system01.dbfinput datafile file number=00003 name=/home/oracle/oradata/pcc/sysaux01.dbfinput datafile file number=00004 name=/home/oracle/oradata/pcc/undotbs01.dbfinput datafile file number=00005 name=/home/oracle/oradata/pcc/tbs_zyq01.dbfinput datafile file number=00007 name=/home/oracle/oradata/pcc/users01.dbfchannel ORA_DISK_1: starting piece 1 at 28-JUN-18channel ORA_DISK_1: finished piece 1 at 28-JUN-18piece handle=/home/oracle/bak/db_01t6k254_1_1 tag=TAG20180628T215236 comment=NONEchannel ORA_DISK_1: backup set complete, elapsed time: :15Finished backup at 28-JUN-18Starting Control File and SPFILE Autobackup at 28-JUN-18piece handle=/u01/app/oracle/product/12.2.0.1/dbs/c-3164878903-20180628-00 comment=NONEFinished Control File and SPFILE Autobackup at 28-JUN-182.3 恢复表
[oracle@localhost ~]$ rman target /Recovery Manager: Release 12.2.0.1.0 - Production on Fri Jun 29 00:52:29 2018Copyright (c) 1982, 2017, Oracle and/or its affiliates. All rights reserved.connected to target database: PCC (DBID=3164878903)RMAN> RECOVER TABLE zyq.t_recover_testuntil time "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh24:mi:ss')"AUXILIARY DESTINATION '/data01'REMAP TABLE zyq.t_recover_test:t_recover_test_map;2> 3> 4>Starting recover at 29-JUN-18using target database control file instead of recovery catalogallocated channel: ORA_DISK_1channel ORA_DISK_1: SID=66 device type=DISKRMAN-05026: warning: presuming following set of tablespaces applies to specified point-in-timeList of tablespaces expected to have UNDO segmentsTablespace SYSTEMTablespace UNDOTBS1Creating automatic instance, with SID='hCed'initialization parameters used for automatic instance_db_name=PCCdb_unique_name=hCed_pitr_PCCcompatible=12.2.0db_block_size=8192db_files=200diagnostic_dest=/u01/app/oracle_system_trig_enabled=FALSEsga_target=732Mprocesses=200db_create_file_dest=/data01log_archive_dest_1='location=/data01'#No auxiliary parameter file usedstarting up automatic instance PCCOracle instance startedTotal System Global Area 767557632 bytesFixed Size 8625416 bytesVariable Size 213910264 bytesDatabase Buffers 541065216 bytesRedo Buffers 3956736 bytesAutomatic instance createdcontents of Memory Script:{# set requested point in timeset until time "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh24:mi:ss')";# restore the controlfilerestore clone controlfile;# mount the controlfilesql clone 'alter database mount clone database';# archive current online logsql 'alter system archive log current';}executing Memory Scriptexecuting command: SET until clauseStarting restore at 29-JUN-18allocated channel: ORA_AUX_DISK_1channel ORA_AUX_DISK_1: SID=35 device type=DISKchannel ORA_AUX_DISK_1: starting datafile backup set restorechannel ORA_AUX_DISK_1: restoring control filechannel ORA_AUX_DISK_1: reading from backup piece /u01/app/oracle/product/12.2.0.1/dbs/c-3164878903-20180628-01channel ORA_AUX_DISK_1: piece handle=/u01/app/oracle/product/12.2.0.1/dbs/c-3164878903-20180628-01 tag=TAG20180628T234914channel ORA_AUX_DISK_1: restored backup piece 1channel ORA_AUX_DISK_1: restore complete, elapsed time: :02output file name=/data01/PCC/controlfile/o1_mf_fmcsc00p_.ctlFinished restore at 29-JUN-18sql statement: alter database mount clone databasesql statement: alter system archive log currentcontents of Memory Script:{# set requested point in timeset until time "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh24:mi:ss')";# set destinations for recovery set and auxiliary set datafilesset 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 tempfilesswitch clone tempfile all;# restore the tablespaces in the recovery set and the auxiliary setrestore clone datafile 1, 4, 3;switch clone datafile all;}executing Memory Scriptexecuting command: SET until clauseexecuting command: SET NEWNAMEexecuting command: SET NEWNAMEexecuting command: SET NEWNAMEexecuting command: SET NEWNAMErenamed tempfile 1 to /data01/PCC/datafile/o1_mf_temp_%u_.tmp in control fileStarting restore at 29-JUN-18using channel ORA_AUX_DISK_1channel ORA_AUX_DISK_1: starting datafile backup set restorechannel ORA_AUX_DISK_1: specifying datafile(s) to restore from backup setchannel ORA_AUX_DISK_1: restoring datafile 00001 to /data01/PCC/datafile/o1_mf_system_%u_.dbfchannel ORA_AUX_DISK_1: restoring datafile 00004 to /data01/PCC/datafile/o1_mf_undotbs1_%u_.dbfchannel ORA_AUX_DISK_1: restoring datafile 00003 to /data01/PCC/datafile/o1_mf_sysaux_%u_.dbfchannel ORA_AUX_DISK_1: reading from backup piece /home/oracle/bak/db_01t6k254_1_1channel ORA_AUX_DISK_1: piece handle=/home/oracle/bak/db_01t6k254_1_1 tag=TAG20180628T215236channel ORA_AUX_DISK_1: restored backup piece 1channel ORA_AUX_DISK_1: restore complete, elapsed time: :15Finished restore at 29-JUN-18datafile 1 switched to datafile copyinput datafile copy RECID=4 STAMP=980038406 file name=/data01/PCC/datafile/o1_mf_system_fmcsc755_.dbfdatafile 4 switched to datafile copyinput datafile copy RECID=5 STAMP=980038406 file name=/data01/PCC/datafile/o1_mf_undotbs1_fmcsc75h_.dbfdatafile 3 switched to datafile copyinput datafile copy RECID=6 STAMP=980038406 file name=/data01/PCC/datafile/o1_mf_sysaux_fmcsc75c_.dbfcontents of Memory Script:{# set requested point in timeset until time "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh24:mi:ss')";# online the datafiles restored or switchedsql 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 onlyrecover clone database tablespace "SYSTEM", "UNDOTBS1", "SYSAUX";sql clone 'alter database open read only';}executing Memory Scriptexecuting command: SET until clausesql statement: alter database datafile 1 onlinesql statement: alter database datafile 4 onlinesql statement: alter database datafile 3 onlineStarting recover at 29-JUN-18using channel ORA_AUX_DISK_1starting media recoveryarchived log for thread 1 with sequence 3 is already on disk as file /u01/app/oracle/product/12.2.0.1/dbs/arch1_3_979872889.dbfarchived log for thread 1 with sequence 4 is already on disk as file /u01/app/oracle/product/12.2.0.1/dbs/arch1_4_979872889.dbfarchived log file name=/u01/app/oracle/product/12.2.0.1/dbs/arch1_3_979872889.dbf thread=1 sequence=3archived log file name=/u01/app/oracle/product/12.2.0.1/dbs/arch1_4_979872889.dbf thread=1 sequence=4media recovery complete, elapsed time: :11Finished recover at 29-JUN-18sql statement: alter database open read onlycontents 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 databasesql clone 'alter database mount clone database';}executing Memory Scriptsql statement: create spfile from memorydatabase closeddatabase dismountedOracle instance shut downconnected to auxiliary database (not started)Oracle instance startedTotal System Global Area 767557632 bytesFixed Size 8625416 bytesVariable Size 213910264 bytesDatabase Buffers 541065216 bytesRedo Buffers 3956736 bytessql statement: alter system set control_files = ''/data01/PCC/controlfile/o1_mf_fmcsc00p_.ctl'' comment= ''RMAN set'' scope=spfileOracle instance shut downconnected to auxiliary database (not started)Oracle instance startedTotal System Global Area 767557632 bytesFixed Size 8625416 bytesVariable Size 213910264 bytesDatabase Buffers 541065216 bytesRedo Buffers 3956736 bytessql statement: alter database mount clone databasecontents of Memory Script:{# set requested point in timeset until time "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh24:mi:ss')";# set destinations for recovery set and auxiliary set datafilesset newname for datafile 5 to new;# restore the tablespaces in the recovery set and the auxiliary setrestore clone datafile 5;switch clone datafile all;}executing Memory Scriptexecuting command: SET until clauseexecuting command: SET NEWNAMEStarting restore at 29-JUN-18allocated channel: ORA_AUX_DISK_1channel ORA_AUX_DISK_1: SID=34 device type=DISKchannel ORA_AUX_DISK_1: starting datafile backup set restorechannel ORA_AUX_DISK_1: specifying datafile(s) to restore from backup setchannel ORA_AUX_DISK_1: restoring datafile 00005 to /data01/HCED_PITR_PCC/datafile/o1_mf_tbs_zyq_%u_.dbfchannel ORA_AUX_DISK_1: reading from backup piece /home/oracle/bak/db_01t6k254_1_1channel ORA_AUX_DISK_1: piece handle=/home/oracle/bak/db_01t6k254_1_1 tag=TAG20180628T215236channel ORA_AUX_DISK_1: restored backup piece 1channel ORA_AUX_DISK_1: restore complete, elapsed time: :03Finished restore at 29-JUN-18datafile 5 switched to datafile copyinput datafile copy RECID=8 STAMP=980038478 file name=/data01/HCED_PITR_PCC/datafile/o1_mf_tbs_zyq_fmcsfttn_.dbfcontents of Memory Script:{# set requested point in timeset until time "to_date('2018-06-28 23:56:06','yyyy-mm-dd hh24:mi:ss')";# online the datafiles restored or switchedsql clone "alter database datafile 5 online";# recover and open resetlogsrecover clone database tablespace "TBS_ZYQ", "SYSTEM", "UNDOTBS1", "SYSAUX" delete archivelog;alter clone database open resetlogs;}executing Memory Scriptexecuting command: SET until clausesql statement: alter database datafile 5 onlineStarting recover at 29-JUN-18using channel ORA_AUX_DISK_1starting media recoveryarchived log for thread 1 with sequence 3 is already on disk as file /u01/app/oracle/product/12.2.0.1/dbs/arch1_3_979872889.dbfarchived log for thread 1 with sequence 4 is already on disk as file /u01/app/oracle/product/12.2.0.1/dbs/arch1_4_979872889.dbfarchived log file name=/u01/app/oracle/product/12.2.0.1/dbs/arch1_3_979872889.dbf thread=1 sequence=3archived log file name=/u01/app/oracle/product/12.2.0.1/dbs/arch1_4_979872889.dbf thread=1 sequence=4media recovery complete, elapsed time: :01Finished recover at 29-JUN-18database openedcontents of Memory Script:{# create directory for datapump importsql "create or replace directory TSPITR_DIROBJ_DPDIR as ''/data01''";# create directory for datapump exportsql clone "create or replace directory TSPITR_DIROBJ_DPDIR as ''/data01''";}executing Memory Scriptsql 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 :35Export completedcontents of Memory Script:{# shutdown clone before importshutdown clone abort}executing Memory ScriptOracle instance shut downPerforming 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 :45Import completedRemoving automatic instanceAutomatic instance removedauxiliary instance file /data01/PCC/datafile/o1_mf_temp_fmcsd5ny_.tmp deletedauxiliary instance file /data01/HCED_PITR_PCC/onlinelog/o1_mf_3_fmcsg3y6_.log deletedauxiliary instance file /data01/HCED_PITR_PCC/onlinelog/o1_mf_2_fmcsg07o_.log deletedauxiliary instance file /data01/HCED_PITR_PCC/onlinelog/o1_mf_1_fmcsfzr1_.log deletedauxiliary instance file /data01/HCED_PITR_PCC/datafile/o1_mf_tbs_zyq_fmcsfttn_.dbf deletedauxiliary instance file /data01/PCC/datafile/o1_mf_sysaux_fmcsc75c_.dbf deletedauxiliary instance file /data01/PCC/datafile/o1_mf_undotbs1_fmcsc75h_.dbf deletedauxiliary instance file /data01/PCC/datafile/o1_mf_system_fmcsc755_.dbf deletedauxiliary instance file /data01/PCC/controlfile/o1_mf_fmcsc00p_.ctl deletedauxiliary instance file tspitr_hCed_71393.dmp deletedFinished recover at 29-JUN-18RMAN>2.4 验证
SQL> select count(*) from T_RECOVER_TEST_MAP; COUNT(*)---------- 726524. 总结
（1） 根据为恢复指定的时间点确定哪个备份包含需要恢复的表或表分区。
（2） 确定目标主机上是否有足够的空间来创建将在表或分区恢复过程中使用的辅助实例。如果所需空间不可用，则RMAN会显示错误并退出恢复操作。
（3） 在目标主机上创建一个辅助数据库，并将指定的表或表分区恢复到此辅助数据库中，直到指定的时间点。您可以指定恢复的数据文件存储在辅助数据库中的目标主机上的位置。
（4） 创建包含恢复的表或表分区的数据泵导出转储文件。您可以指定用于存储恢复的表或表分区的元数据的数据泵导出转储文件的名称和位置。
（5） （可选）将Data Pump导出转储文件导入到目标实例中。您可以选择不将包含恢复的表或表分区的导出转储文件导入目标数据库。如果不将导出转储文件作为恢复过程的一部分导入，则必须稍后使用“数据泵导入”实用程序手动导入它。
注：如果在导入操作期间发生错误，RMAN不会在表恢复结束时删除导出转储文件。这使您能够手动导入转储文件。
（6） （可选）重命名目标数据库中已恢复的表或表分区。您还可以将恢复的对象导入到与最初存在的表空间或模式不同的表空间或模式中。12.2开始，schema可不同
注：当您使用REMAP选项时，不会导入任何指定的约束和索引。这是为了避免与现有表格的名称冲突。
如果不希望表被导入，只需要恢复出dmp文件，可以使用notableimport选项，命令如下：
RECOVER TABLE SCOTT.EMP, SCOTT.DEPT UNTIL TIME 'SYSDATE-1' AUXILIARY DESTINATION '/tmp/oracle/recover' DATAPUMP DESTINATION '/tmp/recover/dumpfiles' DUMP FILE 'emp_dept_exp_dump.dat' NOTABLEIMPORT;
如果需要将表恢复至另外的schema，命令如下：
RECOVER TABLE HR.DEPARTMENTS, SH.CHANNELS
UNTIL TIME 'SYSDATE – 1' AUXILIARY DESTINATION '/tmp/auxdest'
REMAP TABLE hr.departments:example.new_departments, sh.channels:example.new_channels;
