Note: Sometimes, if more buffer space is needed, LGWR writes redo log entries before a transaction is committed. These entries become permanent only if the transaction is later committed.

• 有时,如果重做日志缓冲区内空间不足,LGWR进程会在事务提交前就将重做日志条目写入磁盘。这样的重做日志条目只有在相关事务提交后才能永久地存储。