If your reports are predefined - summarised and no adhoc reporting needed, you can look into the continuous view feature of PipelineDB - http://docs.pipelinedb.com/continuous-views.html

> As soon as a stream row has been read by the continuous views that must read it, it is discarded. Raw, granular data is not stored anywhere. The only data that is persisted for a continuous view is whatever is returned by running a SELECT * FROM that_view. Thus you can think of a continuous view as a very high-throughput, realtime materialized view.

I use PipelineDB continuous views in Freshlytics - https://github.com/sheshbabu/freshlytics/blob/master/src/ser...

TimescaleDB also has something called "Continuous Aggregates" - https://docs.timescale.com/latest/using-timescaledb/continuo... but I haven't looked into it much.