[TOC] # reduce内存 调大reduce内存，限制每个reduce处理的数据量 ~~~ set mapreduce.reduce.memory.mb=16384; set mapreduce.reduce.java.opts=-Xmx16384m; set hive.exec.reducers.bytes.per.reducer = 100000000; ~~~ # reduce个数 ~~~ set mapred.reduce.tasks = 2000; set mapreduce.reduce.memory.mb=16384; set mapreduce.reduce.java.opts=-Xmx16384m; ~~~