[LukeEF]

RDF triples turn out to be a crucial part of the architecture as they make describing deltas really straightforward. It is just these triples were added and these triples were taken away. Performance is good - you get a degradation in query time as you build more appended layers, but you can squash these to a single plane to speed up. Often we have a query branch where the layers are optimized for query and another branch with all the commit history in place. We are working on something we call Delta roll ups at the moment - these are like squashes that keep the history. Hopefully you'll soon be able to automate the roll ups to keep query performance at a specified level (something like the vacuum cleaner in postgres). It is in-memory, so you are limited to what's in RAM for querying, but it persists to disk, and we are betting that memory is going to get bigger and cheaper over the next while.