Funny I built the same kind of distributed timeseries system for Digital Ocean, called Vulcan. Also did a few talks on it. It was based around prometheus, I've seen at least 4-5 other major ones that are in production at different places, like Heroku has their own internal one also. Go seems to be the leading language for these next gen databases.
https://www.youtube.com/watch?v=likpVWB5Lvo
https://www.slideshare.net/MatthewCampbell7/distributed-time...