不过，直观地讲，我们会期望数据中有两个主要的循环：每天和每年的(晚上和冬天冷)。
But intuitively, we would expect two primary cycles in the data: daily and yearly (nights and winters are cold).
这可能是因为时间或CPU的代价比较昂贵，或者是因为它们期望数据处于“合适的”状态。
It might be because they are expensive in time or CPU or because they expect data to be in a "decent" state.
数据统计信息中的变化会引起对存取方案的选择发生变化，该存取方案作为访问所期望数据的最有效方法。
A change in the data statistics can result in a change in the choice of access plan selected as the most efficient method of accessing the desired data.
应用推荐