从源码看:
reduceBykey与groupbykey:
都调用函数combineByKeyWithClassTag[V]((v: V) => v, func, func, partitioner)
reduceBykey的map端进行聚合combine操作
mapSideCombine = true
groupbykey的mapSideCombine = false
hejunhong 2020-05-17 17:55 原文
从源码看:
reduceBykey与groupbykey:
都调用函数combineByKeyWithClassTag[V]((v: V) => v, func, func, partitioner)
reduceBykey的map端进行聚合combine操作
mapSideCombine = true
groupbykey的mapSideCombine = false