I've already look at http://pumpkindb.org/ but finally use TrailDB. Else, there's also the leading InfluxDB for Time-Series DB. But if the volume isn't very high, a MySQL/PGSQL could satisfy no?
Is volume the only thing that we go for Time-Series DB? I doubt if Time-Series DB really satisfies the need of "Event sourcing" such as single/multiple column(s) aggregation, etc.