分类目录归档：Oracle备份恢复

遇到一个案例,数据库open报ORA-16038,ORA-00354等错误

SQL> alter database datafile 5 offline;

Database altered.

--使用一些技巧让数据库无法归档

SQL> select group#,status,archived from v$log;

    GROUP# STATUS           ARC
---------- ---------------- ---
         1 INACTIVE         NO
         2 ACTIVE           NO
         3 CURRENT          NO

SQL> shutdown abort;
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.

Total System Global Area  626327552 bytes
Fixed Size                  2255832 bytes
Variable Size             234882088 bytes
Database Buffers          385875968 bytes
Redo Buffers                3313664 bytes
Database mounted.
SQL> alter database clear unarchived logfile group 1;
alter database clear unarchived logfile group 1
*
ERROR at line 1:
ORA-00393: log 1 of thread 1 is needed for recovery of offline datafiles
ORA-00312: online log 1 thread 1: '/u01/app/oracle/oradata/orcl/redo01.log'
ORA-01110: data file 5: '/u01/app/oracle/oradata/orcl/t_xifenfei01.dbf'

SQL> !oerr ora 393
00393, 00000, "log %s of thread %s is needed for recovery of offline datafiles"
// *Cause:  Log cannot be cleared because the redo in it is needed to recover
//          offline datafiles. It has not been archived so there is no
//          other copy available. If the log is cleared the tablespaces
//          containing the files will have to be dropped.
// *Action: Archive the log then repeat the clear command. If archiving is not
//          possible, and dropping the tablespaces is acceptible, then add the
//          clause UNRECOVERABLE DATAFILE at the end of the clear command.


SQL>  alter database clear unarchived logfile group 1 unrecoverable datafile;

Database altered.

SQL> select group#,status,archived from v$log;

    GROUP# STATUS           ARC
---------- ---------------- ---
         1 UNUSED           YES
         3 CURRENT          NO
         2 ACTIVE           NO

客户的问题也是通过unrecoverable datafile 方式强制clear联机日志成功,数据库open成功