It's not that incredible; for most use-cases there is often an optimal(or "better") way to implement a solution that's specifically designed and implemented to

It's not that incredible; for most use-cases there is often an optimal(or "better") way to implement a solution that's specifically designed and implemented to support it, as opposed to relying on systems and designs that are broadly applicable/useful (e.g RDBMS). We just figured out exactly what we wanted, stored the data in chunks, compressed(we used 2 var-int encoding schemes, and snappy compression), indices(skip-lists) for each file and each chunk and for queries, we parellize access to as files required across multiple OS threads (scatter-gather). In fact, I am sure we could have gotten better performance if we wanted to spend more time on that problem. It wasn't novel or particularly interesting or hard anyway. Just something that needed to be done to help us solve a problem.