Thanks for this comment. That's really interesting. It seems like caching is becoming more and more important at every level of the system. Even GPUs are getting DRAM caches now. So "do much with little data at a time" is the way to go.

P.S. I work on Hadoop. "Do little with much data" is a pretty good high level description of what we do. Our single-node efficiency is not what I'd like it to be, but it's improving with next generation SQL and other execution engines.