It is very nice approach which means database never needs to “ stall ” to perform total modified pages flush but instead flushing of dirty pages happens gradually in small chunks so database load is very even 这种做法意味着数据库无需因为需要刷新所有的被修改的内存页而被“拖延” ，它是把所有产生的脏内存页分成多个小块渐渐地刷新，这样负载就比较平均了。
