索引很好地加快了查询地速度，有时将执行的时间减少到以前占用时间的一小部分。
Indexes typically speed up queries, sometimes reducing the time required to execute the query to a fraction of the former elapsed time.
索引很好地加快了查询地速度，有时将执行的时间减少到以前占用时间的一小部分。
Indexes typically speed up queries, sometimes reducing the time required to execute the query to a fraction of the former elapsed time.
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