MapReduce

Data parallel text processing with MapReduce.

This is one my solution for this common problem using MapReduce. The best way to process any task is to split it in several chunks and divide the work amongst several 'workers' in a distributed way and then compose the results in a later stage.

For this problem I am using MapReduce approach using LINQ and .NET 4.6.

Processing the file sequentially and keeping the results in a dictionary is an easy task but with a really bad performance. Using MapReduce strategy we could split the work and then combine the results in a concurrent dictionary:

Example usage:

Reducer reducer = new Reducer();
try
{
    string readText = File.ReadAllText(args[0]);
    Console.WriteLine("Starting reduction");
    reducer.MapReduce(readText);
    Console.WriteLine("Reduction completed");
    File.WriteAllText("Results.txt", reducer.SortedResults().ToString());
    Console.WriteLine("Done!, processing {0:D} words", reducer.Numwords);
    Console.WriteLine("Please review Results.txt");

}
catch (Exception ex)
{
    Console.WriteLine(ex.Message);                
}

Benchmark testing:

• This solution can count 500k workds in 400ms using 1 processor with 4 cores.
• Download the version 1.0 from here. https://app.box.com/s/jfh684sgqtp0it856fvcv6186sssn3m3

Licence

The MIT License (MIT)

Copyright (c) 2015 Jordi Corbilla

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