[tstonez]

Ideally open-source. Surprised MongoDB 2.2+ is such an issue but thanks for the feedback and suggestions. We'll look into PostgreSQL, Riak and RethinkDB.

[bduerst]

It is based on an open-sourced db called Dremel:

https://code.google.com/p/dremel/

[yipjustin]

But dremel doesn't support incremental updates. Dremel is designed for read-only data. All its columns are indexed. The whole table needs to be re-built after update.