Nice presentation - it confirms what I've been doing for a few years now in terms of how to best represent/store financial data in particular full OB depth and trades data. Plain old binary files stored in a columnar manner - one file for each column be it Time, Depth Levels, or Trades. Fully portable across all platforms and applications. On top of that I use FastBit plus my own access layer to query data. Also very easy and quick to map that data into memory if needed. Never tried OneTick or KDB but any other DB I tried was miserably worse.