我引入Python实现的运行时间作为基线；该版本完全没有优化。

I included the running time of the Python implementation as a baseline; this version is completely non-optimized.

youdao

有时候客户报告的性能问题中说某个特定查询的执行没有优化。

Sometimes customers report a performance problem where a specific query is not performing optimally.

youdao

例如，如果这两个本地谓词选择性没有优化器评估的强，怎么办？

For example, what if the two local predicates are not as selective as estimated by the optimizer?

youdao