查询优化¶
约 86 个字 8 张图片 预计阅读时间不到 1 分钟
Intro¶
- An evaluation plan defines exactly what algorithm is used for each operation, and how the execution of the operations is coordinated.
Equivalent¶
- 上面的式子左右可以相互转换
- 自然连接可交换、结合
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Select往叶子上push
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$\theta _2上面有索引$
Statistics for Cost Estimation¶
Size Estimation
Choice of Evaluation Plans¶
局部最优不一定全局最优