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  • Book Overview & Buying Hadoop MapReduce v2 Cookbook - Second Edition: RAW
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Hadoop MapReduce v2 Cookbook - Second Edition: RAW

Hadoop MapReduce v2 Cookbook - Second Edition: RAW - Second Edition

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Hadoop MapReduce v2 Cookbook - Second Edition: RAW

Hadoop MapReduce v2 Cookbook - Second Edition: RAW

4.4 (7)

Overview of this book

If you are a Big Data enthusiast and wish to use Hadoop v2 to solve your problems, then this book is for you. This book is for Java programmers with little to moderate knowledge of Hadoop MapReduce. This is also a one-stop reference for developers and system admins who want to quickly get up to speed with using Hadoop v2. It would be helpful to have a basic knowledge of software development using Java and a basic working knowledge of Linux.
Table of Contents (12 chapters)
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11
Index

Calculating frequency distributions and sorting using MapReduce


Frequency distribution is the number of hits received by each URL sorted in ascending order. We already calculated the number of hits for each URL in the earlier recipe. This recipe will sort that list based on the number of hits.

Getting ready

This recipe assumes that you have a working Hadoop installation. This recipe will use the results from the Performing GROUP BY using MapReduce recipe of this chapter. Follow this recipe if you have not done so already.

How to do it...

The following steps show how to calculate frequency distribution using MapReduce:

  1. Run the MapReduce job using the following command. We assume that the data/hit-count-out path contains the output of the HitCountMapReduce computation of the previous recipe:

    $ bin/hadoop jar hcb-c5-samples.jar \
    chapter5.weblog.FrequencyDistributionMapReduce \
    data/hit-count-out data/freq-dist-out
    
  2. Read the results by running the following command:

    $ hdfs dfs -cat data/freq-dist...
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Hadoop MapReduce v2 Cookbook - Second Edition: RAW
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