Off-topic but the author's paper (from 2008) about C-store databases is a really good overview and survey of column-oriented databases and why/how they are useful. Which I understood at the basic conceptual level but never dug into in detail (ie, implementation details) as my day-to-day work is mostly in the web app row-by-row world: http://cs-www.cs.yale.edu/homes/dna/papers/abadiphd.pdf