清除受损的复用联机重做日志

alter database clear logfile

不能清除活动的联机日志，如果数据库位于archivelog模式中，则清除组必须归档；

select * from v$log;

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-01624: log 3 needed for crash recovery of instance test (thread 1)
ORA-00312: online log 3 thread 1: 'D:\ORACLE\ORADATA\TEST\REDO03.LOG'

尝试清除2，成功，尝试清除3，失败；

SQL> alter system switch logfile;

System altered.

select * from v$log;

SQL> alter system checkpoint;

System altered.

在此清除第三组，成功；

SQL> alter database clear logfile group 3;

Database altered.