熊猫的非唯一索引对性能有什么影响?。

What is the performance impact of non-unique indexes in pandas?

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通常情况下，在基础索引提供好处(如唯一索引访问、避免排序或一些类似的好处)时，可通过优化器选择非匹配索引扫描。

Typically, a non-matching index scan is chosen by the optimizer when the underlying index provides benefits such as index-only access, avoids sort, or some similar benefit.

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例如，非唯一元素能够阻止您正确评估执行较少索引查询的代码。

For example, non-unique element names can keep you from properly evaluating code that performs fewer index look-ups.

youdao

例如，非唯一元素能够阻止您正确评估执行较少索引查询的代码。

For example, non-unique element names can keep you from properly evaluating code that performs fewer index look-ups.

youdao