This is a completely different beast in terms of expected query latency (sub-second) and as a result has different constraints about structure of data, amount of data queried and cost naturally.

You can think of Pinot and Druid as solving for the real-time analytics cases, like say for instance you run an ad network and you want to provide your customers with a live dashboard of ad impressions and allow segmentation of that dashboard by cohorts and other metrics on the fly.