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

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.

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>