探索ORACLE不完全恢复之--基于cancel恢复 第一篇

探索ORACLE不完全恢复之--基于cancel恢复 第一篇
作者：吴伟龙 Name：Prodence Woo
QQ：286507175 msn:hapy-wuweilong@hotmail.com





基于cancel的不一致性恢复（归档存在） 第一篇





基于取消的恢复只适用于以下情况：归档日志丢失导致完全恢复失败；丢失了数据文件和未归档的重做日志（联机重做日志）；



1、先关闭数据库，执行一次全库冷备份。



SQL> selectfile_name from dba_data_files;



FILE_NAME

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

/DBBak2/oradata/WWL/users01.dbf

/DBBak2/oradata/WWL/sysaux01.dbf

/DBBak2/oradata/WWL/undotbs01.dbf

/DBBak2/oradata/WWL/system01.dbf

/DBBak2/oradata/WWL/WWL001.dbf

/DBBak2/oradata/WWL/WWL002.dbf

/DBBak2/oradata/WWL/WWL003.dbf



7 rows selected.



SQL> shutdownimmediate

Database closed.

Database dismounted.

ORACLE instance shut down.



SQL> !mkdir/DBBak2/oradata/WWL2



SQL> !cp/DBBak2/oradata/WWL/* /DBBak2/oradata/WWL2/





2、然后打开数据库继续使用，我们可以看到备份的时候数据库wwl001表中只有4条记录。

SQL> select * fromwwl001;



ID NAME

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

1 jetsen

2 woo

3 prudence

4 beijin

4 rows selected.



3、继续向wwl001表中插入数据，并切换日志让redo log归档。

SQL> insert intowwl001 values(5,'china');

1 row created.



SQL> insert intowwl001 values(6,'america');

1 row created.



SQL> commit;

Commit complete.



SQL> select * fromwwl001;



ID NAME

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

1 jetsen

2 woo

3 prudence

4 beijin

5 china

6 america



6 rows selected.



SQL>



SQL> alter systemswitch logfile;

System altered.



SQL> /

System altered.



SQL> /

System altered.



SQL> /

System altered.



SQL> /

System altered.



4、关闭数据库，模拟数据文件丢失，归档日志也丢失了，所以数据库只能做不一致性恢复。

SQL> shutdownabort;

ORACLE instance shut down.



SQL> !rm -rf/DBBak2/oradata/WWL/*.dbf



SQL> !cp/DBBak2/oradata/WWL2/*.dbf /DBBak2/oradata/WWL/



SQL> !cp /DBBak2/oradata/WWL2/*.dbf/DBBak2/oradata/WWL/



5、执行基于取消的不完全恢复

SQL> startup

ORACLE instance started.



Total System Global Area 100663296 bytes

Fixed Size 1217884 bytes

Variable Size 88083108 bytes

Database Buffers 8388608 bytes

Redo Buffers 2973696 bytes

Database mounted.

ORA-01113: file 1 needs media recovery

ORA-01110: data file 1:'/DBBak2/oradata/WWL/system01.dbf'



SQL>select * fromv$recover_file;



FILE# ONLINE ONLINE_ ERROR CHANGE# TIME

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

1 ONLINE ONLINE 1783695 31-JUL-12

2 ONLINE ONLINE 1783695 31-JUL-12

3 ONLINE ONLINE 1783695 31-JUL-12

4 ONLINE ONLINE 1783695 31-JUL-12

5 ONLINE ONLINE 1783695 31-JUL-12

6 ONLINE ONLINE 1783695 31-JUL-12

7 ONLINE ONLINE 1783695 31-JUL-12



7 rows selected.



SQL> recoverdatabase until cancel;

ORA-00279: change 1783695 generated at07/31/2012 15:32:04 needed for thread 1

ORA-00289: suggestion :/DBSoft/product/10.2.0/db_1/dbs/arch/1_2_790095025.dbf

ORA-00280: change 1783695 for thread 1 isin sequence #2





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

cancel

Media recovery cancelled.

SQL>



SQL> select * fromv$recover_file;



FILE# ONLINE ONLINE_ ERROR CHANGE# TIME

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

1 ONLINE ONLINE 1783695 31-JUL-12

2 ONLINE ONLINE 1783695 31-JUL-12

3 ONLINE ONLINE 1783695 31-JUL-12

4 ONLINE ONLINE 1783695 31-JUL-12

5 ONLINE ONLINE 1783695 31-JUL-12

6 ONLINE ONLINE 1783695 31-JUL-12

7 ONLINE ONLINE 1783695 31-JUL-12



7 rows selected.



SQL> alterdatabase open resetlogs;



Database altered.



SQL> conn wwl/wwl

Connected.



SQL> select * fromwwl001;



ID NAME

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

1 jetsen

2 woo

3 prudence

4 beijin



SQL>