Oracle丢失active或current日志文件的恢复操作过程

丢失活动或当前日志文件的恢复
Oracle通过日志文件保证提交成功的数据不丢失,可是在故障中,用户可能损失了当前的(current)日志文件.这又分为两种情况:此时数据是正常关闭的和此时数据库是异常关闭.
1.在损失当前日志时,数据库是正常关闭的.
由于关闭数据库前,oracle会执行全面检查点,当前日志在实例恢复中可以不再需要.
下面进行测试(数据库运行在非归档模式下).在oracle9i及以后版本中,是无法对当前日志进行clear,需要通过until cancel恢复后再以resetlogs方式打开
[oracle@jingyong ~]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Mon Jan 7 00:39:59 2013

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options

SQL> select * from v$version where rownum<2;

BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod

SQL> select * from v$logfile;

    GROUP# STATUS  TYPE
---------- ------- -------
MEMBER
--------------------------------------------------------------------------------
IS_
---
        3        ONLINE
/u01/app/oracle/product/10.2.0/oradata/jingyong/redo03.log
NO

        2        ONLINE
/u01/app/oracle/product/10.2.0/oradata/jingyong/redo02.log
NO

    GROUP# STATUS  TYPE
---------- ------- -------
MEMBER
--------------------------------------------------------------------------------
IS_
---

        1        ONLINE
/u01/app/oracle/product/10.2.0/oradata/jingyong/redo01.log
NO

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.

SQL> !mv /u01/app/oracle/product/10.2.0/oradata/jingyong/redo* /u01/app/oracle

SQL> startup
ORACLE instance started.

Total System Global Area  167772160 bytes
Fixed Size                  1218316 bytes
Variable Size              62916852 bytes
Database Buffers          100663296 bytes
Redo Buffers                2973696 bytes
Database mounted.
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1:
'/u01/app/oracle/product/10.2.0/oradata/jingyong/redo01.log'

SQL> alter database clear logfile group 1;

Database altered.

SQL> alter database clear logfile group 2;

Database altered.

SQL> alter database clear logfile group 3;
alter database clear logfile group 3
*
ERROR at line 1:
ORA-00313: open failed for members of log group 3 of thread 1
ORA-00312: online log 3 thread 1:
'/u01/app/oracle/product/10.2.0/oradata/jingyong/redo03.log'
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3

SQL> select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES    MEMBERS ARC STATUS
---------- ---------- ---------- ---------- ---------- --- ----------------
FIRST_CHANGE# FIRST_TIME
------------- ------------
        1          1          0  52428800          1 NO  UNUSED
            0 06-JAN-13

        3          1          0  52428800          1 NO  CLEARING_CURRENT
      914164 06-JAN-13

        2          1          0  52428800          1 NO  UNUSED
      914157 06-JAN-13

SQL> recover database until cancel;
Media recovery complete.

SQL> alter database open resetlogs;

Database altered.

SQL>