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fetchType 默认为 collect 会有较大的性能问题 #1872

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allwefantasy opened this issue Oct 31, 2022 · 1 comment

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allwefantasy commented Oct 31, 2022

需要修改为 fetchType=take

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allwefantasy commented Oct 31, 2022

collect 使用了非 end limit ,这个 limit 限制条数会导致一次shuffle, 这会产生几个问题：

额外的shuffle 导致性能下降
会导致只是查看表数据的优化失效，产生全表扫描。
Spark 3.3.0 一些 Command 返回的结果会导致顺序问题

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