[FeatureStore] We should be using doubles instead of longs where at all possible

[cjnolet]

I ran into this recently. I have a bunch of sampled sensor data that I want to represent in the metrics store but it's got floating points, which we can't represent with the current Metric object. The fix was extremely simple and it will not break data that's already been persisted.

[eawagner]

I think this would be a good idea. For the sum and sum squared portions of the metrics service, you might want to represent them as BigDecimal however, or you may have some precision loss.

[cjnolet]

yep. That one was easy too.