If Google was a boxer then MapReduce would be a probing right hand that sets up the massive left hook that is Dremel, Google's—scalable (thousands of CPUs, petabytes of data, trillions of rows), SQL based, columnar, interactive (results returned in seconds), ad-hoc—analytics system. If Google was a magician then MapReduce would be the shiny thing that distracts the mind while the trick goes unnoticed. I say that because even though Dremel has been around internally at Google since 2006, we have not heard a whisper about it. All we've heard about is MapReduce, clones of which have inspired entire new industries. Tricky.

Dremel, according to Brian Bershad, Director of Engineering at Google, is targeted at solving BigData class problems:

While we all know that systems are huge and will get even huger, the implications of this size on programmability, manageability, power, etc. is hard to comprehend. Alfred noted that the Internet is predicted to be carrying a zetta-byte (1021 bytes) per year in just a few years. And growth in the number of processing elements per chip may give rise to warehouse computers of having 1010 or more processing elements. To use systems at this scale, we need new solutions for storage and computation.