When a data file is placed in backup mode, more of redo log may be generated because the log writer writes block images of changed blocks of the data file in backup mode to redo log instead of just the row information.
Backup mode中会产生更多的redo log ，原因是LGWR不仅仅记录row info,它还记录了些什么别的东东?
请问在opened DB backup时它还额外记录了些什么信息呢？
