HeteroTSDB: An Extensible Time Series Database on Heterogeneous Key-Value Stores [pdf] (yuuk.io)

Or normalize your data and use clickhouse.

I scanned this, and there's a lot of talk here about having two separate layers of key-value storage (not nearly the first system to have that design), but I'm missing what is the key innovation here. I need to read it in more detail, but if anyone else figures out what that is, I'd love to hear about it.