Chapter 13. Working with MapReduce

MongoDB is a document-based database used to tackle large amounts of data and is used by companies such as Forbes, Bitly, Foursquare, Craigslist, and so on. In Chapter 12, Data Processing and Aggregation with MongoDB, we learned how to perform the basic operations and aggregations with MongoDB. In this chapter, we will learn how MongoDB implements a MapReduce programming model.

In this chapter we will cover:

• MapReduce overview

• Programming model

• Using MapReduce with MongoDB

  • The map function

  • The reduce function

  • Using mongo shell

  • Using UMongo

  • Using PyMongo

• Filtering the input collection

• Grouping and aggregation

• The most common words in tweets in a word-cloud visualization

You can find a list of production deployments of MongoDB at http://www.mongodb.org/about/production-deployments/.