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:
Using MapReduce with MongoDB
Using mongo shell
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/.