基于scn的恢复是怎样的

今天就跟大家聊聊有关基于scn的恢复是怎样的，可能很多人都不太了解，为了让大家更加了解，小编给大家总结了以下内容，希望大家根据这篇文章可以有所收获。

--先背备份：（热备）

[oracle@wang ~]$ rman target /

Recovery Manager: Release 11.2.0.4.0 - Production on Fri Dec 8 19:35:11 2017

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database: DBDB (DBID=3282897732)

RMAN> backup database;

Starting backup at 08-DEC-17
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=44 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=00004 name=/u01/app/oracle/oradata/DBdb/users01.dbf
input datafile file number=00006 name=/u01/app/oracle/fast_recovery_area/DBDB/newback/ts_xxf_01.dbf
input datafile file number=00001 name=/u01/app/oracle/oradata/DBdb/system01.dbf
input datafile file number=00003 name=/u01/app/oracle/oradata/DBdb/undotbs01.dbf
channel ORA_DISK_1: starting piece 1 at 08-DEC-17
channel ORA_DISK_1: finished piece 1 at 08-DEC-17
piece handle=/u01/app/oracle/fast_recovery_area/DBDB/newback/DBDB/backupset/2017_12_08/o1_mf_nnndf_TAG20171208T193949_f2nyj5gy_.bkp tag=TAG20171208T193949 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:55
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00002 name=/u01/app/oracle/oradata/DBdb/sysaux01.dbf
input datafile file number=00005 name=/u01/app/oracle/oradata/DBdb/example01.dbf
channel ORA_DISK_1: starting piece 1 at 08-DEC-17
 channel ORA_DISK_1: finished piece 1 at 08-DEC-17
piece handle=/u01/app/oracle/fast_recovery_area/DBDB/newback/DBDB/backupset/2017_12_08/o1_mf_nnndf_TAG20171208T193949_f2nykwl2_.bkp tag=TAG20171208T193949 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:25
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 08-DEC-17
channel ORA_DISK_1: finished piece 1 at 08-DEC-17
piece handle=/u01/app/oracle/fast_recovery_area/DBDB/newback/DBDB/backupset/2017_12_08/o1_mf_ncsnf_TAG20171208T193949_f2nylpqk_.bkp tag=TAG20171208T193949 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 08-DEC-17

RMAN>     


二、模拟操作：
SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    3960846

SQL>  
SQL> create table scott.scn_a as select * from dba_objects;

Table created.

SQL> select count(*) from scott.scn_a;

  COUNT(*)
----------
     87053

SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    3960968

SQL>
SQL> create table hr.scn_b as select * from dba_objects;

Table created.

SQL> select count(*) from hr.scn_b;

  COUNT(*)
----------
     87054

SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    3961042

SQL>        
SQL> alter system switch logfile;

System altered.

SQL>
SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    3961063

SQL>
SQL> alter system checkpoint;

System altered.

SQL>
SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    3961088

--删除表scn_a/scn_b:
SQL> drop table scott.scn_a purge;

Table dropped.

SQL> drop table hr.scn_b purge;

Table dropped.


--进行恢复：
--关库，启动到mount状态:
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL>
SQL> startup mount;
ORACLE instance started.

Total System Global Area  835104768 bytes
Fixed Size                  2257840 bytes
Variable Size             549456976 bytes
Database Buffers          281018368 bytes
Redo Buffers                2371584 bytes
Database mounted.
SQL>

启用rman进行恢复：
[oracle@wang ~]$ rman target /

Recovery Manager: Release 11.2.0.4.0 - Production on Fri Dec 8 19:49:38 2017

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database: DBDB (DBID=3282897732, not open)

RMAN>      

RMAN> run {  
    set until scn =3960968;  
    restore database;  
    recover database;  
    alter database open resetlogs; }

executing command: SET until clause

Starting restore at 08-DEC-17
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=20 device type=DISK

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 /u01/app/oracle/oradata/DBdb/system01.dbf
channel ORA_DISK_1: restoring datafile 00003 to /u01/app/oracle/oradata/DBdb/undotbs01.dbf
channel ORA_DISK_1: restoring datafile 00004 to /u01/app/oracle/oradata/DBdb/users01.dbf
channel ORA_DISK_1: restoring datafile 00006 to /u01/app/oracle/fast_recovery_area/DBDB/newback/ts_xxf_01.dbf
channel ORA_DISK_1: reading from backup piece /u01/app/oracle/fast_recovery_area/DBDB/newback/DBDB/backupset/2017_12_08/o1_mf_nnndf_TAG20171208T193949_f2nyj5gy_.bkp
  channel ORA_DISK_1: piece handle=/u01/app/oracle/fast_recovery_area/DBDB/newback/DBDB/backupset/2017_12_08/o1_mf_nnndf_TAG20171208T193949_f2nyj5gy_.bkp tag=TAG20171208T193949
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:02:15
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 00002 to /u01/app/oracle/oradata/DBdb/sysaux01.dbf
channel ORA_DISK_1: restoring datafile 00005 to /u01/app/oracle/oradata/DBdb/example01.dbf
channel ORA_DISK_1: reading from backup piece /u01/app/oracle/fast_recovery_area/DBDB/newback/DBDB/backupset/2017_12_08/o1_mf_nnndf_TAG20171208T193949_f2nykwl2_.bkp
channel ORA_DISK_1: piece handle=/u01/app/oracle/fast_recovery_area/DBDB/newback/DBDB/backupset/2017_12_08/o1_mf_nnndf_TAG20171208T193949_f2nykwl2_.bkp tag=TAG20171208T193949
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:25
Finished restore at 08-DEC-17

Starting recover at 08-DEC-17
using channel ORA_DISK_1

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

Finished recover at 08-DEC-17

database opened

RMAN>   

--验证：
SQL> select status from v$instance;

STATUS
------------
OPEN

SQL> select count(*) from scott.scn_a;

  COUNT(*)
----------
     87053

SQL>
SQL> select count(*) from hr.scn_b;
select count(*) from hr.scn_b
                        *
ERROR at line 1:
ORA-00942: table or view does not exist

因为恢复时只是恢复到创建scn_a表后查询到的current_scn，此时表scn_b还没有创建。

看完上述内容，你们对基于scn的恢复是怎样的有进一步的了解吗？如果还想了解更多知识或者相关内容，请关注编程网数据库频道，感谢大家的支持。