[stingraycharles]

You should look into proprietary technologies, there are some very compelling offerings there. I have personally used QuasarDB ( https://www.quasardb.net/ ), and can say that it's on par with kdb+ in terms of performance, scales horizontally and has support for transactions and secondary indexes. They have a single node free edition as well.

Typically these solutions tend to follow the money, but if you ignore the list price, you can usually get a decent deal for a startup.

[jnordwick]

I know there are other proprietary dbs out there. I was speaking of FOSS/open databases any cant they come even without an order of magnitude of commercial offerings. Quasar would be included in that commercial group.

I'm only slightly familiar with Quasar, but I believe it is just a key-value store with document characterists, not a general database. The comparisons on their website are mostly to other KV stores and document systems.