#MapJoin

mapjoin与reducejoin

一、mapjoin1.Mapper类packagecom.css.mapjoin;importjava.io.BufferedReader;importjava.io.FileInputStream;importjava.io.IOException;importjava.io.InputStreamReader;im...
代码星球 ·2020-12-18

MapJoin和ReduceJoin区别及优化

https://blog.csdn.net/qq_17776287/article/details/78567514...

Hive开启mapjoin优化、并行执行、动态分区

1. mapjoin优化适合小表join大表sethive.optimize.skewjoin=true;//有数据倾斜时开启负载均衡,默认falsesethive.auto.convert.join=true;//设置自动选择MapJoin,默认是truesethive.auto.convert.join....