使用RMAN对CDB和PDB执行按时间点恢复
RMAN能够对CDB与PDB执行按时间点恢复操作。但是PDB只能使用RMAN来执行按时间点恢复。如是没有使用恢复目录数据库，建议启用自动控制文件备份。否则当对PDB执行按时间点恢复时，当RMAN需要增加与删除undo数据文件时不能有效的执行。
PDB按时间点恢复与快速恢复区
当对PDB执行数据库按时间点恢复时，对于这个PDB所有的数据文件都将被执行恢复操作。然而，为了将PDB恢复到指定的时间点，RMAN在恢复目标时间点也是需要有UNDO表空间存在的。因为undo表空间是被所有PDB所共享的，它不能被恢复。RMAN会将root中的undo,system与sysaux表空间还原到辅助实例中，然后使用undo信息来将pdb恢复到指定的时间点。如果配置了快速恢复区，Oracle将会使用它作为辅助实例的存储目录。如果快速恢复区没有被配置，那么必须使用auxiliary destination子句来指定辅助实例数据库文件的存储目录。确保在快速恢复区有足够的空间可以用来还原root表空间与undo表空间。如果快速恢复区没有足够的空间，可以通过使用auxiliary destination子句来指定其它的目录。
对CDB执行数据库按时间点恢复
1.登录数据库记录当前SCN号，然后将表t1中的数据删除。
SQL> conn jy/jy@jypdb
Connected.
SQL> SELECT CURRENT_SCN FROM V$DATABASE;
CURRENT_SCN
-----------
6041183
SQL> alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';
Session altered.
SQL> select sysdate from dual;
SYSDATE
-------------------
2017-12-18 18:28:30
SQL> select count(*) from t1;
COUNT(*)
----------
39
SQL> truncate table t1;
Table truncated.
SQL> select count(*) from t1;
COUNT(*)
----------
0
2.如果使用时间表达式来代替目标SCN，那么在调用RMAN之前设置时间格式环境变量
[oracle@jytest1 ~]$ export NLS_DATE_FORMAT='yyyy-mm-dd hh24:mi:ss'
3.使用RMAN连接到root容器
[oracle@jytest1 ~]$ rman target/ catalog rco/xxzx7817600@jypdb_173 Recovery Manager: Release 12.2.0.1.0 - Production on Mon Dec 18 18:32:00 2017 Copyright (c) 1982, 2017, Oracle and/or its affiliates. All rights reserved. connected to target database: JY (DBID=979425723) connected to recovery catalog database
4.将CDB重启到mount状态
RMAN> shutdown immediate starting full resync of recovery catalog full resync complete database closed database dismounted Oracle instance shut down RMAN> startup mount connected to target database (not started) Oracle instance started database mounted Total System Global Area 6442450944 bytes Fixed Size 8807168 bytes Variable Size 1895828736 bytes Database Buffers 4529848320 bytes Redo Buffers 7966720 bytes starting full resync of recovery catalog full resync complete
5.使用RUN块来执行以下操作
a.对于数据库按时间点鶋，使用set until来指定恢复的目标时间，scn或日志序列号，或者使用set to来指定还原点。如果指定时间那么使用环境变量nls_lang与nls_date_format中所指定的日期格式。
b.如果RMAN没有配置自动通道，那么需要手动分配磁盘与磁带通道。
c.还原与恢复CDB
下面的命令将CDB恢复到SCN=6041183所在的状态
RMAN> run
2> {
3> set until scn 6041183;
4> restore database;
5> recover database;
6> }
executing command: SET until clause
Starting restore at 2017-12-18 18:46:50
flashing back control file to SCN 6041183
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=764 instance=jy1 device type=DISK
skipping datafile 5; already restored to file +DATA/JY/5F9AA264B21F3ED9E053AB828A0A6088/DATAFILE/system.256.962209675
skipping datafile 6; already restored to file +DATA/JY/5F9AA264B21F3ED9E053AB828A0A6088/DATAFILE/sysaux.270.962209675
skipping datafile 8; already restored to file +DATA/JY/5F9AA264B21F3ED9E053AB828A0A6088/DATAFILE/undotbs1.296.962209675
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 00001 to +DATA/JY/DATAFILE/system.317.962209603
channel ORA_DISK_1: restoring datafile 00003 to +DATA/JY/DATAFILE/sysaux.298.962209605
channel ORA_DISK_1: restoring datafile 00004 to +DATA/JY/DATAFILE/undotbs1.277.962209605
channel ORA_DISK_1: restoring datafile 00007 to +DATA/JY/DATAFILE/users.301.962209605
channel ORA_DISK_1: restoring datafile 00009 to +DATA/JY/DATAFILE/undotbs2.312.962209605
channel ORA_DISK_1: reading from backup piece +TEST/rman_backup/jy_979425723_962563410_10slv3ai_1_1
channel ORA_DISK_1: piece handle=+TEST/rman_backup/jy_979425723_962563410_10slv3ai_1_1 tag=TAG20171212T184328
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:01:05
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 00010 to +DATA/JY/5F9AC6865E87549FE053AB828A0ADE94/DATAFILE/system.271.962209649
channel ORA_DISK_1: restoring datafile 00011 to +DATA/JY/5F9AC6865E87549FE053AB828A0ADE94/DATAFILE/sysaux.316.962209649
channel ORA_DISK_1: restoring datafile 00012 to +DATA/JY/5F9AC6865E87549FE053AB828A0ADE94/DATAFILE/undotbs1.264.962209649
channel ORA_DISK_1: restoring datafile 00013 to +DATA/JY/5F9AC6865E87549FE053AB828A0ADE94/DATAFILE/undo_2.268.962209649
channel ORA_DISK_1: restoring datafile 00014 to +DATA/JY/5F9AC6865E87549FE053AB828A0ADE94/DATAFILE/users.278.962209649
channel ORA_DISK_1: restoring datafile 00015 to +DATA/JY/5F9AC6865E87549FE053AB828A0ADE94/DATAFILE/test.275.962210609
channel ORA_DISK_1: reading from backup piece +TEST/rman_backup/jy_979425723_962563516_11slv3ds_1_1
channel ORA_DISK_1: piece handle=+TEST/rman_backup/jy_979425723_962563516_11slv3ds_1_1 tag=TAG20171212T184328
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:35
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 00016 to +DATA/JY/600D6F56DEB669CCE053AB828A0AAB7E/DATAFILE/system.260.962469409
channel ORA_DISK_1: restoring datafile 00017 to +DATA/JY/600D6F56DEB669CCE053AB828A0AAB7E/DATAFILE/sysaux.259.962469409
channel ORA_DISK_1: restoring datafile 00018 to +DATA/JY/600D6F56DEB669CCE053AB828A0AAB7E/DATAFILE/undotbs1.265.962469409
channel ORA_DISK_1: restoring datafile 00019 to +DATA/JY/600D6F56DEB669CCE053AB828A0AAB7E/DATAFILE/undo_2.266.962469409
channel ORA_DISK_1: restoring datafile 00020 to +DATA/JY/600D6F56DEB669CCE053AB828A0AAB7E/DATAFILE/users.267.962469409
channel ORA_DISK_1: restoring datafile 00021 to +DATA/JY/600D6F56DEB669CCE053AB828A0AAB7E/DATAFILE/test.269.962469409
channel ORA_DISK_1: reading from backup piece +TEST/rman_backup/jy_979425723_962563551_12slv3ev_1_1
channel ORA_DISK_1: piece handle=+TEST/rman_backup/jy_979425723_962563551_12slv3ev_1_1 tag=TAG20171212T184328
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:35
Finished restore at 2017-12-18 18:49:09
Starting recover at 2017-12-18 18:49:11
using channel ORA_DISK_1
applied offline range to datafile 00010
offline range RECID=80 STAMP=963072332
applied offline range to datafile 00011
offline range RECID=79 STAMP=963072332
applied offline range to datafile 00012
offline range RECID=78 STAMP=963072332
applied offline range to datafile 00013
offline range RECID=77 STAMP=963072332
applied offline range to datafile 00014
offline range RECID=76 STAMP=963072332
applied offline range to datafile 00015
offline range RECID=75 STAMP=963072332
applied offline range to datafile 00016
offline range RECID=86 STAMP=963072332
applied offline range to datafile 00017
offline range RECID=85 STAMP=963072332
applied offline range to datafile 00018
offline range RECID=84 STAMP=963072332
applied offline range to datafile 00019
offline range RECID=83 STAMP=963072332
applied offline range to datafile 00020
offline range RECID=82 STAMP=963072332
applied offline range to datafile 00021
offline range RECID=81 STAMP=963072332
starting media recovery
archived log for thread 1 with sequence 34 is already on disk as file +TEST/arch/1_34_961976319.dbf
archived log for thread 1 with sequence 35 is already on disk as file +TEST/arch/1_35_961976319.dbf
archived log for thread 1 with sequence 36 is already on disk as file +TEST/arch/1_36_961976319.dbf
archived log for thread 1 with sequence 37 is already on disk as file +TEST/arch/1_37_961976319.dbf
archived log for thread 1 with sequence 38 is already on disk as file +TEST/arch/1_38_961976319.dbf
archived log for thread 1 with sequence 39 is already on disk as file +TEST/arch/1_39_961976319.dbf
archived log for thread 1 with sequence 40 is already on disk as file +TEST/arch/1_40_961976319.dbf
archived log for thread 1 with sequence 41 is already on disk as file +TEST/arch/1_41_961976319.dbf
archived log for thread 1 with sequence 42 is already on disk as file +TEST/arch/1_42_961976319.dbf
archived log for thread 1 with sequence 43 is already on disk as file +TEST/arch/1_43_961976319.dbf
archived log for thread 1 with sequence 44 is already on disk as file +TEST/arch/1_44_961976319.dbf
archived log for thread 1 with sequence 45 is already on disk as file +TEST/arch/1_45_961976319.dbf
archived log for thread 1 with sequence 46 is already on disk as file +TEST/arch/1_46_961976319.dbf
archived log for thread 1 with sequence 47 is already on disk as file +TEST/arch/1_47_961976319.dbf
archived log for thread 1 with sequence 48 is already on disk as file +TEST/arch/1_48_961976319.dbf
archived log for thread 1 with sequence 49 is already on disk as file +TEST/arch/1_49_961976319.dbf
archived log for thread 1 with sequence 50 is already on disk as file +TEST/arch/1_50_961976319.dbf
archived log for thread 1 with sequence 51 is already on disk as file +TEST/arch/1_51_961976319.dbf
archived log for thread 1 with sequence 52 is already on disk as file +DATA/JY/ONLINELOG/group_2.302.961976321
archived log for thread 1 with sequence 53 is already on disk as file +DATA/JY/ONLINELOG/group_1.261.961976319
archived log for thread 2 with sequence 28 is already on disk as file +TEST/arch/2_28_961976319.dbf
archived log for thread 2 with sequence 29 is already on disk as file +TEST/arch/2_29_961976319.dbf
archived log for thread 2 with sequence 30 is already on disk as file +TEST/arch/2_30_961976319.dbf
archived log for thread 2 with sequence 31 is already on disk as file +TEST/arch/2_31_961976319.dbf
archived log for thread 2 with sequence 32 is already on disk as file +TEST/arch/2_32_961976319.dbf
archived log for thread 2 with sequence 33 is already on disk as file +TEST/arch/2_33_961976319.dbf
archived log for thread 2 with sequence 34 is already on disk as file +TEST/arch/2_34_961976319.dbf
archived log for thread 2 with sequence 35 is already on disk as file +TEST/arch/2_35_961976319.dbf
archived log for thread 2 with sequence 36 is already on disk as file +TEST/arch/2_36_961976319.dbf
archived log for thread 2 with sequence 37 is already on disk as file +TEST/arch/2_37_961976319.dbf
archived log for thread 2 with sequence 38 is already on disk as file +TEST/arch/2_38_961976319.dbf
archived log for thread 2 with sequence 39 is already on disk as file +TEST/arch/2_39_961976319.dbf
archived log for thread 2 with sequence 40 is already on disk as file +TEST/arch/2_40_961976319.dbf
archived log for thread 2 with sequence 41 is already on disk as file +TEST/arch/2_41_961976319.dbf
archived log for thread 2 with sequence 42 is already on disk as file +TEST/arch/2_42_961976319.dbf
archived log for thread 2 with sequence 43 is already on disk as file +TEST/arch/2_43_961976319.dbf
archived log for thread 2 with sequence 44 is already on disk as file +TEST/arch/2_44_961976319.dbf
archived log for thread 2 with sequence 45 is already on disk as file +TEST/arch/2_45_961976319.dbf
archived log for thread 2 with sequence 46 is already on disk as file +TEST/arch/2_46_961976319.dbf
archived log for thread 2 with sequence 47 is already on disk as file +TEST/arch/2_47_961976319.dbf
archived log for thread 2 with sequence 48 is already on disk as file +TEST/arch/2_48_961976319.dbf
archived log for thread 2 with sequence 49 is already on disk as file +TEST/arch/2_49_961976319.dbf
archived log for thread 2 with sequence 50 is already on disk as file +TEST/arch/2_50_961976319.dbf
archived log for thread 2 with sequence 51 is already on disk as file +TEST/arch/2_51_961976319.dbf
archived log for thread 2 with sequence 52 is already on disk as file +DATA/JY/ONLINELOG/group_4.262.961976705
archived log for thread 2 with sequence 53 is already on disk as file +DATA/JY/ONLINELOG/group_3.263.961976697
archived log file name=+TEST/arch/1_34_961976319.dbf thread=1 sequence=34
archived log file name=+TEST/arch/2_28_961976319.dbf thread=2 sequence=28
archived log file name=+TEST/arch/1_35_961976319.dbf thread=1 sequence=35
archived log file name=+TEST/arch/2_29_961976319.dbf thread=2 sequence=29
archived log file name=+TEST/arch/1_36_961976319.dbf thread=1 sequence=36
archived log file name=+TEST/arch/2_30_961976319.dbf thread=2 sequence=30
archived log file name=+TEST/arch/2_31_961976319.dbf thread=2 sequence=31
archived log file name=+TEST/arch/1_37_961976319.dbf thread=1 sequence=37
archived log file name=+TEST/arch/2_32_961976319.dbf thread=2 sequence=32
archived log file name=+TEST/arch/1_38_961976319.dbf thread=1 sequence=38
archived log file name=+TEST/arch/2_33_961976319.dbf thread=2 sequence=33
archived log file name=+TEST/arch/1_39_961976319.dbf thread=1 sequence=39
archived log file name=+TEST/arch/2_34_961976319.dbf thread=2 sequence=34
archived log file name=+TEST/arch/1_40_961976319.dbf thread=1 sequence=40
archived log file name=+TEST/arch/2_35_961976319.dbf thread=2 sequence=35
archived log file name=+TEST/arch/1_41_961976319.dbf thread=1 sequence=41
archived log file name=+TEST/arch/2_36_961976319.dbf thread=2 sequence=36
archived log file name=+TEST/arch/1_42_961976319.dbf thread=1 sequence=42
archived log file name=+TEST/arch/2_37_961976319.dbf thread=2 sequence=37
archived log file name=+TEST/arch/2_38_961976319.dbf thread=2 sequence=38
archived log file name=+TEST/arch/1_43_961976319.dbf thread=1 sequence=43
archived log file name=+TEST/arch/2_39_961976319.dbf thread=2 sequence=39
archived log file name=+TEST/arch/1_44_961976319.dbf thread=1 sequence=44
archived log file name=+TEST/arch/2_40_961976319.dbf thread=2 sequence=40
archived log file name=+TEST/arch/1_45_961976319.dbf thread=1 sequence=45
archived log file name=+TEST/arch/2_41_961976319.dbf thread=2 sequence=41
archived log file name=+TEST/arch/1_46_961976319.dbf thread=1 sequence=46
archived log file name=+TEST/arch/2_42_961976319.dbf thread=2 sequence=42
archived log file name=+TEST/arch/2_43_961976319.dbf thread=2 sequence=43
archived log file name=+TEST/arch/1_47_961976319.dbf thread=1 sequence=47
archived log file name=+TEST/arch/2_44_961976319.dbf thread=2 sequence=44
archived log file name=+TEST/arch/2_45_961976319.dbf thread=2 sequence=45
archived log file name=+TEST/arch/1_48_961976319.dbf thread=1 sequence=48
archived log file name=+TEST/arch/2_46_961976319.dbf thread=2 sequence=46
archived log file name=+TEST/arch/1_49_961976319.dbf thread=1 sequence=49
archived log file name=+TEST/arch/2_47_961976319.dbf thread=2 sequence=47
archived log file name=+TEST/arch/2_48_961976319.dbf thread=2 sequence=48
archived log file name=+TEST/arch/1_50_961976319.dbf thread=1 sequence=50
archived log file name=+TEST/arch/2_49_961976319.dbf thread=2 sequence=49
archived log file name=+TEST/arch/1_51_961976319.dbf thread=1 sequence=51
archived log file name=+TEST/arch/2_50_961976319.dbf thread=2 sequence=50
archived log file name=+TEST/arch/2_51_961976319.dbf thread=2 sequence=51
media recovery complete, elapsed time: 00:08:44
Finished recover at 2017-12-18 18:58:02
6.执行以下互斥操作
.以读写方式打开CDB，放弃目标SCN之后的所有改变。在这种情况下，你必须将CDB重启到mount状态后，然后执行以下命令
alter database open resetlogs
.使用Data Pump导出CDB中你所需要的对象。然后将CDB恢复到当前时间点并重新导入对象，因此可以将需要的对象进行恢复而不用放弃所有其它对象所发生的改变。
RMAN> alter database open read only;
Statement processed
RMAN> alter pluggable database all open read only;
Statement processed
SQL> conn jy/jy@jypdb
Connected.
SQL> select count(*) from t1;
COUNT(*)
----------
39
RMAN> shutdown immediate
database closed
database dismounted
Oracle instance shut down
RMAN> startup mount
connected to target database (not started)
Oracle instance started
database mounted
Total System Global Area 6442450944 bytes
Fixed Size 8807168 bytes
Variable Size 1895828736 bytes
Database Buffers 4529848320 bytes
Redo Buffers 7966720 bytes
RMAN> recover database;
Starting recover at 2017-12-18 22:26:55
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=10 instance=jy1 device type=DISK
starting media recovery
media recovery complete, elapsed time: 00:00:05
Finished recover at 2017-12-18 22:27:05
RMAN> alter database open;
Statement processed
starting full resync of recovery catalog
full resync complete
RMAN> alter pluggable database all open read write;
Statement processed
starting full resync of recovery catalog
full resync complete