环境 虚拟机:VMware 10 Linux版本:CentOS-6.5-x86_64 客户端:Xshell4 FTP:Xftp4 jdk8 hadoop-3.1.1 最应该推荐的好友TopN,如何排名? tom hello hadoop cat world hadoop hello hive cat tom hive mr hive hello hive cat hadoop world hello mr hadoop tom hive world hello tom world hive mr…
一.概述 1.map-reduce是什么 Hadoop MapReduce is a software framework for easily writing applications which process vast amounts of data (multi-terabyte data-sets) in-parallel on large clusters (thousands of nodes) of commodity hardware in a reliable, fault-…
In the last post we saw how to write a MapReduce program for finding the top-n items of a dataset. The code in the mapper emits a pair key-value for every word found, passing the word as the key and 1 as the value. Since the book has roughly 38,000 w…
In this post we'll see how to count the top-n items of a dataset; we'll again use the flatland book we used in a previous post: in that example we used the WordCount program to count the occurrences of every single word forming the book; now we want…
