We ended up using Postgres 10 w/ TimeScaleDB and their Prometheus plugin with a simple emulated push gateway that converts a prom formatted http post to a postgres batch insert. Postgres is 3 nodes monitored with Patroni.
Working great for us and handling 1000+ metrics a second with ease and we get SQL for both real-time metrics for monitoring and analytics for business needs. We are using about 10-15% of our systems giving us room to grow.