Not everyone feels comfortable with MapReduce even if at first glance it looks pretty simple. Considering how useful and used MapReduce is in the NoSQL world, I thought it would be useful to put together a quick guide to MapReduce.
If the whole notion is completely unfamiliar to you, Kristina Kchodorow’s(@kchodorow) ☞ post should get you started using a Star Trek-based story.
The next very detailed and visual explanation of MapReduce is Oren Eini’s (@ayende) ☞ post. While the post relies on Linq to explain MapReduce, all steps are accompanied by nice images.
There is also this ☞ article by Joel Spolsky and the ☞ Stackoverflow answers.
In case by now you’ve already started to ask yourself how would you translate some SQL functionality you’ll probably find ☞ pdf showing a SQL to (MongoDB) MapReduce translation:
While probably not as clear as the other examples above, Pete Warden’s (@peterwarden) “MapReduce for Idiots”:
Once you are done with this, I think you have enough details to read the ☞ original paper from Google and why not even continue with some MapReduce and Hadoop academic papers: