Amazon Elastic MapReduce

Based on Hadoop, MapReduce equips users with potent distributed data-processing tools

Amazon Web Services Elastic MapReduce
  • Expert Rating

    Not yet rated

Pros

  • Doesn't take long to get the hang of

Cons

  • Currently available in the US region only

Bottom Line

You'll want to be familiar with the Apache Hadoop framework before you jump into Elastic MapReduce. It doesn't take long to get the hang of it, though. Most developers can have a MapReduce application running within a few hours.

Would you buy this?

  • Price

    TBA (AUD)

Have you got a few hundred gigabytes of data that need processing? Perhaps a dump of radio telescope data that could use some combing through by a squad of processors running Fourier transforms? Or maybe you're convinced some statistical analysis will reveal a pattern hidden in several years of stock market information? Unfortunately, you don't happen to have a grid of distributed processors to run your application, much less the time to construct a parallel processing infrastructure.

Well, cheer up: Amazon has added Elastic MapReduce to its growing list of cloud-based Web services. Currently in beta, Elastic MapReduce uses Amazon's Elastic Compute Cloud (EC2) and Simple Storage Service (S3) to implement a virtualized distributed processing system based on Apache Hadoop.

Hadoop's internal architecture is the MapReduce framework. The mechanics of MapReduce are well documented in a paper by J. Dean and S. Ghemawat [PDF], and a full treatment is beyond the scope of this article. Instead, I'll illustrate by example.

Suppose you have a set of 10 words and you want to count the number of times those words appear in a collection of e-books. Your input data is a set of key/value pairs, the value being a line of text from one of the books and the key being the concatenation of the book's name and the line's number. This set might comprise a few megabytes big -- or gigabytes. MapReduce doesn't much care about size.

You write a routine that reads this input, a pair at a time, and produces another key/value pair as output. The output key is a word (from the original set of 10) and the associated value is the number of times that word appears in the line. (Zero values are not emitted.) This routine is the map part of map/reduce. Its output is referred to as the intermediate key/value pairs.

The intermediate key/value pairs are fed to another function (another "step" in the parlance of MapReduce). For this step, you write a routine that iterates through the intermediate data, sums up the values, and returns a single pair whose key is the word and whose value is the grand total. You don't have to worry about grouping the results of like keys (i.e., gathering all the intermediate key/values for a given word), because Hadoop does that grouping for you in the background.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Show Comments

Brand Post

Shining a light on creativity

MSI has long pushed the boundaries of invention with its ever-evolving range of laptops but it has now pulled off a world first with the new MSI Creative 17.

Most Popular Reviews

Latest News Articles

Resources

PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers

MSI P65

This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang

MSI GT76

It really doesn’t get more “gaming laptop” than this.

Jack Jeffries

MSI GS75

As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr

MSI PS63

The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?