本文介绍了如何写'仅地图'hadoop工作?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我是hadoop的新手,我对map-reduce编程的风格很熟悉,但现在我遇到了一个问题:有时候我只需要映射一个工作,我只需要map结果直接作为输出,这意味着减少阶段在这里是不需要的,我怎样才能达到目的?

这会关闭reducer。

  job.setNumReduceTasks(0); 


I'm a novice on hadoop, I'm getting familiar to the style of map-reduce programing but now I faced a problem : Sometimes I need only map for a job and I only need the map result directly as output, which means reduce phase is not needed here, how can I achive that?

解决方案

This turns off the reducer.

job.setNumReduceTasks(0);

http://hadoop.apache.org/docs/current/api/org/apache/hadoop/mapreduce/Job.html#setNumReduceTasks(int)

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08-18 08:27