I was a bit hasty in my posts about MongoStorage for Pig. It seems that complex types are not supported - which limits the value of Pig/Mongo integration. What one wants to do is to process data on Hadoop, and then group it for serving via MongoDB. Without BAGs and TUPLEs, you can’t do this.

So, I used Alan Gates’ awesome book Programming Pig as a guide, and added bags and tuples to MongoStorage (part of mongo-hadoop).

The gist is here: https://gist.github.com/1546174

The pull request is here: https://github.com/mongodb/mongo-hadoop/pull/29