It looks like TrailDB solves a particular problem (which is actually quite common btw) the right way. However the language barrier makes it hard to use it as DB. I believe that Python binding is nice for development environment but in production we would probably want to use a low level language for performance reasons because we'll be dealing with billions of events in a single machine. Do you plan to implement a query language which compiles to native code such as SQL?

How do you handle continuous data with TrailDB? It seems that you store raw events Kinesis, buffer events and periodically write TrailDB files to S3. When you want to process events for a specific user, normally the events might be in a random TrailDB file so the timeline would be mixed up. Do you merge TrailDB files in a single instance when processing the data or have a sharding mechanism?