If you're interested in reading more about the general design of column stores, I can recommend  as a great place to start. It also compares design decisions made in MonetDB to other column stores.
If you want to look at simple code after the reading, I'm slowly implementing a naive column store over at  in golang. The overall structure isn't flexible but the individual columns are quite portable. It has a number of tests and benchmarks using a few months of MTG price data I had sitting around.
For anyone looking for info about column oriented DBs, I can recommend  as a great place to start. It covers the basic optimizations and compares some older solutions at a fairly high level.