应用还原的控制文件进行不完全恢复

应用还原的控制文件进行不完全恢复

条件:归档日志文件完好（可能也会用到redo日志）

描述：有时当我们的数据库的在线日志丢失或损坏，我们可以恢复到最后一次归档的时间的时间点，而不使用redo log时进行不完全恢复，下面就是在没有redo log的情况下的一次不完全恢复实例。

backup datafile + backup controlfile + archivelog file to recover database until time point

--备份数据文件

SQL> alter database begin backup;

Database altered.

SQL> host cp /u01/oracle/oradata/oemgc/*.dbf /u01/oracle/oradata/oemgc_bk

SQL> alter database end backup;--据说这个操作包含了归档操作

Database altered.

SQL> alter system switch logfile;--或是alter system archive log current;

System altered.

SQL> archive log list

Database log mode Archive Mode

Automatic archival Enabled

Archive destination USE_DB_RECOVERY_FILE_DEST

Oldest online log sequence 2

Next log sequence to archive 4

Current log sequence 4

--备份控制文件

SQL> alter database backup controlfile to '/u01/oracle/oradata/ctr.ctl';

Database altered.

SQL> create table a1 as select * from dba_tables;

Table created.

SQL> alter system switch logfile;

System altered.

SQL> archive log list

Database log mode Archive Mode

Automatic archival Enabled

Archive destination USE_DB_RECOVERY_FILE_DEST

Oldest online log sequence 2

Next log sequence to archive 5

Current log sequence 5

--查看当前时间为t1 = 2010-10-20 16:30:19

SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;

TO_CHAR(SYSDATE,'YY

-------------------

2010-10-20 16:30:19

SQL> create table a3 as select * from dba_tables;

Table created.

SQL> alter system switch logfile;

System altered.

SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;

TO_CHAR(SYSDATE,'YY

-------------------

2010-10-20 16:31:25

SQL> archive log list

Database log mode Archive Mode

Automatic archival Enabled

Archive destination USE_DB_RECOVERY_FILE_DEST

Oldest online log sequence 4

Next log sequence to archive 6

Current log sequence 6

SQL> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

--还原控制文件和数据文件

[oracle@DB1 oradata]$ cp ctr.ctl oemgc/control01.ctl

[oracle@DB1 oradata]$ cp ctr.ctl oemgc/control02.ctl

[oracle@DB1 oradata]$ cp ctr.ctl oemgc/control03.ctl

[oracle@DB1 oradata]$ cd oemgc_bk

[oracle@DB1 oemgc_bk]$ cp * ../oemgc

--删除redo log

[oracle@DB1 oemgc_bk]$ cd ../oemgc

[oracle@DB1 oemgc]rm *.log

--恢复数据库到t1时点

SQL> startup mount

ORACLE instance started.

Total System Global Area 289406976 bytes

Fixed Size 1219016 bytes

Variable Size 71304760 bytes

Database Buffers 213909504 bytes

Redo Buffers 2973696 bytes

Database mounted.

SQL> recover database using backup controlfile until time '2010-10-20 16:30:19';

ORA-00279: change 1270337 generated at 10/20/2010 16:19:03 needed for thread 1

ORA-00289: suggestion :

/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_1_%u_.arc

ORA-00280: change 1270337 for thread 1 is in sequence #1

Specify log: {<RET>=suggested | filename | AUTO | CANCEL}

/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_1_6cx9r8ph_.arc

ORA-00279: change 1270439 generated at 10/20/2010 16:23:36 needed for thread 1

ORA-00289: suggestion :

/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_2_%u_.arc

ORA-00280: change 1270439 for thread 1 is in sequence #2

ORA-00278: log file

'/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_1_6cx9r8ph_

.arc' no longer needed for this recovery

Specify log: {<RET>=suggested | filename | AUTO | CANCEL}

/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_2_6cx9tz5f_.arc

ORA-00279: change 1270477 generated at 10/20/2010 16:25:03 needed for thread 1

ORA-00289: suggestion :

/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_3_%u_.arc

ORA-00280: change 1270477 for thread 1 is in sequence #3

ORA-00278: log file

'/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_2_6cx9tz5f_

.arc' no longer needed for this recovery

Specify log: {<RET>=suggested | filename | AUTO | CANCEL}

/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_3_6cx9wrt7_.arc

ORA-00279: change 1270501 generated at 10/20/2010 16:26:00 needed for thread 1

ORA-00289: suggestion :

/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_4_%u_.arc

ORA-00280: change 1270501 for thread 1 is in sequence #4

ORA-00278: log file

'/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_3_6cx9wrt7_

.arc' no longer needed for this recovery

Specify log: {<RET>=suggested | filename | AUTO | CANCEL}

auto

ORA-00279: change 1270797 generated at 10/20/2010 16:30:00 needed for thread 1

ORA-00289: suggestion :

/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_5_%u_.arc

ORA-00280: change 1270797 for thread 1 is in sequence #5

ORA-00278: log file

'/u01/oracle/flash_recovery_area/OEMGC/archivelog/2010_10_20/o1_mf_1_4_6cxb48fg_

.arc' no longer needed for this recovery

Log applied.

Media recovery complete.

---数据库恢复完成，注意这里恢复时只用到了T1时间以前的归档日志进行恢复，没有用到redo日志，所以这里即使redo日志丢失或损坏也能恢复成功。如果要恢复的时间点的数据用到redo日志（也就是数据还没归档），就必需用到在线日志进行恢复。

--恢复到了T1时间点，可以查看数据恢复成功。

SQL> alter database open resetlogs;

Database altered.

SQL> select count(1) from a1;

COUNT(1)

----------

1570

--T1以后的数据已经不存在了。

SQL> select count(1) from a3;

select count(1) from a3

*

ERROR at line 1:

ORA-00942: table or view does not exist

SQL>