它会基于存储在目录和统计表中的统计数据而评估每一个可能的存取计划的执行开销，然后选择最低开销的存取计划。

It estimates the execution cost of each potential access plan based on the statistics data stored in catalog and statistics tables, and selects the one with the lowest cost.

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您可以从以上步骤看到，这个优化器基于可用的统计信息选择了最优的存取计划。

As you've seen in the steps above, the optimizer selects the optimal access plan based on available statistics.

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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.

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