改变在线重做日志文件大小和数量有时是优化数据库。
Changing the size and number of the online redo log files is sometimes done to tune the database.
保存在线重做日志文件组的多个成员来保证重做日志不丢失。
Maintaining multiple members of an online redo log group protects against the loss of the redo log.
你可以在主库添加或删除在线重做日志组或者日志成员而不影响备库。
You can add or drop online redo log file groups or members to the primary database without affecting the standby database.
一般来说，当当前的在线重做日志文件已经满了并且还必须继续写的是偶，日志切换就会发生。
Normally, a switch occurs when the current online redo log file is full and writing must continue.
无论何时，你在主库添加在线重做日志文件，你应该在备库添加相应的在线重做日志和备用重做日志文件。
Whenever you add an online redo log file to the primary database, you should add corresponding online and standby redo log files to the standby database.
理论上说，日志文件组的成员的存放位置应该放在磁盘上的不同位置，这样即使一个磁盘损坏也不会导致整个在线重做日志文件丢失。
Ideally, the locations of the members should be on separate disks so that the failure of one disk does not cause the loss of the entire online redo log.
磁碟央行是这点已刷新LGWR的重做线程的在线日志文件。
The on-disk RBA is the point up to which LGWR has flushed the redo thread to the online log files.
磁碟央行是这点已刷新LGWR的重做线程的在线日志文件。
The on-disk RBA is the point up to which LGWR has flushed the redo thread to the online log files.
应用推荐