两个有趣的REDO LOG ERROR处理方法
系统环境：
操作系统： AIX-5300
数据库： Oracle 10g(10.2.0.1.0)
案例描述：
数据库(归档模式）非当前日志组被破坏，但由于破坏方式不同，在解决问题的方式稍有不同，很有意思.
案例1：非当前日志组文件被删除
SQL> select member from v$logfile;
MEMBER
--------------------------------------------------------------------------------------------------------
/dsk1/oradata/prod/redo03a.log
/dsk1/oradata/prod/redo02a.log
/dsk1/oradata/prod/redo01a.log
/dsk2/oradata/prod/redo01b.log
/dsk2/oradata/prod/redo02b.log
/dsk2/oradata/prod/redo03b.log
6 rows selected.
删除非当前日志组：
[oracle@aix211 ~]$cd /dsk1/oradata/prod/
[oracle@aix211 prod]$ls
control02.ctl redo01a.log redo02a.log redo03a.log
[oracle@aix211 prod]$rm redo01a.log
[oracle@aix211 prod]$cd /dsk2/oradata/prod/
[oracle@aix211 prod]$ls
redo01b.log redo02b.log redo03b.log
[oracle@aix211 prod]$rm redo01b.log
关闭数据库，并重新启动：
SQL> shutdown abort
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 1258291200 bytes
Fixed Size 2020552 bytes
Variable Size 318769976 bytes
Database Buffers 922746880 bytes
Redo Buffers 14753792 bytes
Database mounted.
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '/dsk1/oradata/prod/redo01a.log'
ORA-00312: online log 1 thread 1: '/dsk2/oradata/prod/redo01b.log'
告警日志：（提示：日志组文件找不到，无法读取）
Errors in file /u01/app/oracle/admin/prod/udump/prod_ora_536600.trc:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '/dsk2/oradata/prod/redo01b.log'
ORA-27037: unable to obtain file status
IBM AIX RISC System/6000 Error: 2: No such file or directory
Additional information: 3
ORA-00312: online log 1 thread 1: '/dsk1/oradata/prod/redo01a.log'
ORA-27037: unable to obtain file status
IBM AIX RISC System/6000 Error: 2: No such file or directory
Additional information: 3
Completed: alter database clear logfile group 1
Mon May 26 10:02:36 2014
alter database open
Mon May 26 10:02:36 2014
Block change tracking file is current.
解决方法：
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
1 1 452 52428800 2 YES INACTIVE 806225 26-MAY-14
3 1 451 52428800 2 YES INACTIVE 803970 26-MAY-14
2 1 453 52428800 2 NO CURRENT 806237 26-MAY-14
由于是非当前日志组，并且已经完成归档：
SQL> alter database clear logfile group 1;
Database altered.
打开数据库成功：
SQL> alter database open;
Database altered.
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
1 1 454 52428800 2 NO CURRENT 826578 26-MAY-14
2 1 453 52428800 2 YES INACTIVE 806237 26-MAY-14
3 1 451 52428800 2 YES INACTIVE 803970 26-MAY-14
SQL> alter system switch logfile;
System altered.
案例2：非当前日志组文件头部被破坏
[oracle@aix211 prod]$dd if=/dev/zero of=/dsk1/oradata/prod/redo03a.log bs=8192 count=3
3+0 records in
3+0 records out
[oracle@aix211 prod]$dd if=/dev/zero of=/dsk2/oradata/prod/redo03b.log bs=8192 count=3
3+0 records in
3+0 records out
关库并启动Instance：
SQL> shutdown abort;
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 1258291200 bytes
Fixed Size 2020552 bytes
Variable Size 318769976 bytes
Database Buffers 922746880 bytes
Redo Buffers 14753792 bytes
Database mounted.
ORA-00316: log 3 of thread 1, type in header is not log file
ORA-00312: online log 3 thread 1: '/dsk1/oradata/prod/redo03a.log'
ORA-00312: online log 3 thread 1: '/dsk2/oradata/prod/redo03b.log'
告警日志：（提示：日志组文件头部不可读取）
Errors in file /u01/app/oracle/admin/prod/bdump/prod_lgwr_499718.trc:
ORA-00316: log 3 of thread 1, type 0 in header is not log file
ORA-00312: online log 3 thread 1: '/dsk2/oradata/prod/redo03b.log'
ORA-00316: log 3 of thread 1, type 0 in header is not log file
ORA-00312: online log 3 thread 1: '/dsk1/oradata/prod/redo03a.log'
Mon May 26 10:16:37 2014
解决方法：
Clear非当前日志组：
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
1 1 457 52428800 2 YES INACTIVE 827041 26-MAY-14
3 1 458 52428800 2 YES INACTIVE 827053 26-MAY-14
2 1 459 52428800 2 NO CURRENT 827067 26-MAY-14
SQL> alter database clear logfile group 3;
Database altered.
直接open database失败：
SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-00327: log 3 of thread 1, physical size less than needed
ORA-00312: online log 3 thread 1: '/dsk1/oradata/prod/redo03a.log'
ORA-00312: online log 3 thread 1: '/dsk2/oradata/prod/redo03b.log'
告警日志：（提示：redo 日志组文件头部仍然有错误）
Errors in file /u01/app/oracle/admin/prod/bdump/prod_lgwr_499718.trc:
ORA-00316: log 3 of thread 1, type 0 in header is not log file
ORA-00312: online log 3 thread 1: '/dsk2/oradata/prod/redo03b.log'
ORA-00316: log 3 of thread 1, type 0 in header is not log file
ORA-00312: online log 3 thread 1: '/dsk1/oradata/prod/redo03a.log'
Mon May 26 10:16:37 2014
ARC0: STARTING ARCH PROCESSES
Mon May 26 10:16:37 2014
ORA-316 signalled during: ALTER DATABASE OPEN...
重新启动Instance，重新加载controlfile，问题解决：
SQL> startup force;
ORACLE instance started.
Total System Global Area 1258291200 bytes
Fixed Size 2020552 bytes
Variable Size 318769976 bytes
Database Buffers 922746880 bytes
Redo Buffers 14753792 bytes
Database mounted.
Database opened.
SQL>
以上两个案例都是针对redo log文件被破坏的情况下，解决问题的方法，破坏方式稍有不同，解决方法也有差异，应在实践中注意总结和归纳。
