在ORACLE的运行过程中,总会遇到这样那样的故障,本篇主要大概介绍关于因硬件,系统,误删除等各种原因导致数据库的部分文件丢失,这里列出来由于文件丢失而出现的常见错误和基本处理思路

1.丢失数据文件(ORA-01157)
SQL> startup
ORACLE instance started.

Total System Global Area 260046848 bytes
Fixed Size 1266896 bytes
Variable Size 83888944 bytes
Database Buffers 167772160 bytes
Redo Buffers 7118848 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 4 – see DBWR trace file
ORA-01110: data file 4: ‘/u01/oracle/oradata/XFF/users01.dbf’
数据文件丢失，处理方法：
1).使用备份还原丢失数据然后
2).非undo,system可以offline 掉该文件继续打开数据库
3).如果是undo需要谨慎,可能导致ORA-00376错误
4).如果是system offline可能导致ORA-01147

2. 丢失redo(ORA-00313)
SQL> startup
ORACLE instance started.

Total System Global Area 260046848 bytes
Fixed Size 1266896 bytes
Variable Size 83888944 bytes
Database Buffers 167772160 bytes
Redo Buffers 7118848 bytes
Database mounted.
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: ‘/u01/oracle/oradata/XFF/redo01.log’
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3
redo文件丢失，处理步骤：
1).查询v$log确认该redo是否是current或者active
2).确定该redo是否被归档
3).如果是inactive使用clear 或者 clear unarchived
4).如果是active或者current,需要通过不完全恢复,甚至隐含参数等方法解决

3. 丢失undo(ORA-01092 ORA-00376)
SQL> startup
ORACLE instance started.

Total System Global Area 260046848 bytes
Fixed Size 1266896 bytes
Variable Size 83888944 bytes
Database Buffers 167772160 bytes
Redo Buffers 7118848 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 2 – see DBWR trace file
ORA-01110: data file 2: ‘/u01/oracle/oradata/XFF/undotbs01.dbf’

SQL> alter database datafile 2 offline drop;

Database altered.

SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-01092: ORACLE instance terminated. Disconnection forced

ORA-01092是前台错误,通过查询alert日志发现后台错误主要是：
Fri Oct 25 08:16:36 2013
Errors in file /u01/oracle/admin/XFF/bdump/xff_smon_7437.trc:
ORA-00604: error occurred at recursive SQL level 1
ORA-00376: file 2 cannot be read at this time
ORA-01110: data file 2: ‘/u01/oracle/oradata/XFF/undotbs01.dbf’
因为undo文件丢失,有事务无法正常回滚，从而出现该错误,需要通过使用隐含参数屏蔽事务来解决

4. 丢失system(ORA-01147)
SQL> startup
ORACLE instance started.

Total System Global Area 260046848 bytes
Fixed Size 1266896 bytes
Variable Size 83888944 bytes
Database Buffers 167772160 bytes
Redo Buffers 7118848 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 1 – see DBWR trace file
ORA-01110: data file 1: ‘/u01/oracle/oradata/XFF/system01.dbf’

SQL> alter database datafile 1 offline drop;

Database altered.

SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-01147: SYSTEM tablespace file 1 is offline
ORA-01110: data file 1: ‘/u01/oracle/oradata/XFF/system01.dbf’
system表空间是系统表空间，该表空间中的数据文件不能被offline,如果该表空间数据文件丢失，数据库无法正常方法,可以考虑使用bbed模拟system文件欺骗数据库(非file# 1)或者使用dul抽取数据

5. 丢失控制文件(ORA-00205 ORA-00202)
SQL> startup
ORACLE instance started.

Total System Global Area 260046848 bytes
Fixed Size 1266896 bytes
Variable Size 83888944 bytes
Database Buffers 167772160 bytes
Redo Buffers 7118848 bytes
ORA-00205: error in identifying control file, check alert log for more info

ORA-00205是前台错误，具体需要结合日志分析：
Fri Oct 25 08:35:40 2013
ALTER DATABASE MOUNT
Fri Oct 25 08:35:40 2013
ORA-00202: control file: ‘/u01/oracle/oradata/XFF/control01.ctl’
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3
这里可以看出来，是因为控制问文件丢失该值该错误,处理办法：
1).使用备份控制文件还原
2).查找是否还有其他控制文件，拷贝一份
3).列举数据文件重建控制文件

如果你在使用这些思路进行恢复遇到突发情况不能自行解决,请联系我们,将为您提供专业数据库技术支持
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