If the redo log buffer fills, or another transaction commits, LGWR flushes all of the redo log entries in the redo log buffer to a redo log file, even though some redo records may not be committed.
例如如果重做日志缓沖满了,或者有其它的事务提交了。LGWR进程会把所有在重做日志缓沖中的重做日志事项写入重做文件,即使是一些重做记录可能还没有提交。