[hintymad]

In my particular example, the cardinality of the instances (i.e., the number of of unit instance count in a query's time range) should not even matter. I was summing a counter over all the instances, and VictoriaMetrics should just add up the counters for every time unit while scanning all the data points -- this is implemented by pretty much all the OLAP engines. Or put it another way, logically I was query over a single time series. It's just that each value in the time series was associated with multiple values. Given such logical model, a good time series database should not not even bother me with any concern of cardinality.