惜分飞

我们经常会遇到数据库异常down,然后启动的时候报ORA-00742错误,一般是在recover或者open的过程中遇到

SQL> RECOVER DATABASE;
ORA-00283: 恢复会话因错误而取消
ORA-00742: 日志读取在线程 1 序列 2097 块 296728 中检测到写入丢失情况
ORA-00312: 联机日志 3 线程 1: 'D:\APP\ADMINISTRATOR\ORADATA\HIS\REDO03.LOG'

SQL> recover database;
Media recovery complete.

SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-00742: Log read detects lost write in thread %d sequence %d block %d
ORA-00312: online log 3 thread 1: '/oradata/shrdh/redo03.log'

关于该错误,Oracle官方解释：由于操作系统或者存储或者Oracle导致redo发生写丢失

[oracle@www.xifenfei.com:/home/oracle]$ oerr ora 742
00742, 00000, "Log read detects lost write in thread %s sequence %s block %s"
// *Cause:  Either a write issued by Oracle was lost by the underlying
//          operating system or storage system or an Oracle internal error
//          occurred.
// *Action: The trace file shows the lost write location. Dump the problematic
//          log file to see whether it is a real lost write. Contact Oracle
//          Support Services.

Oracle官方关于ORA-00742的主要bug有:


由于redo写丢失已经发生,一般发生这种情况,有备份使用备份进行不完全恢复,没有备份考虑强制拉库,如果是dg库问题,可以考虑从主库把日志重新传过去