How do I get consistent values with influxdb non_negative_derivative?

Question

Using grafana with influxdb, I am trying to show the per-second rate of some value that is a counter. If I use the non_negative_derivative(1s) function, the value

Answer 1

The problem here is that the $__interval width changes depending on the time frame you are viewing in Grafana.

The way then to get consistent results is to take a sample from each interval (mean(), median(), or max() all work equally well) and then transform by derivative($__interval). That way your derivative changes to match your interval length as you zoom in/out.

So, your query might look like:

SELECT derivative(mean("mem.gc.count"), $__interval) FROM "influxdb"
WHERE $timeFilter GROUP BY time($__interval) fill(null)