Find centralized, trusted content and collaborate around the technologies you use most.
Teams
Q&A for work
Connect and share knowledge within a single location that is structured and easy to search.
我正在运行一个配置单元查询,其中对所有选定的列都应用了 distinct,我注意到有几个 reducer 正在启动以运行相同的查询。谁能解释一下背后的原因?
Example query: > SELECT distinct seg.col1, seg.col2, seg.col3 FROM user.ag_user seg Where ‘2018-05-06’ between start_date and end_date limit 5;
它可能比 x 查询导致 y 减速器稍微复杂一些
这个答案更详细地涵盖了默认情况(比我能做的更好)
默认减速器数量