Calculates the rate for a counter field. This function can show the rate at which a counter changes. The result is returned in a field named _rate with the unit being events/second.
counterAsRate()
is often expected to be
used as the function parameter in a
timeChart()
or
groupBy()
function.
Important
This function requires at least two points for calculating a
rate. When used in a
Time Chart
, it is important to have at least two points in each bucket.
This function expects the field to have monotonic increasing
values over time. If this is not the case no result is returned.
Counters are often reset at server restarts or deployments.
Running rate over a reset would not return a result. Using
counterAsRate()
in a
timeChart()
returns a rate for each bucket
where the counter was not reset and nothing for the buckets
where the counter was reset.
counterAsRate()
Examples
Show the rate of a counter over time:
timeChart(function=counterAsRate(counter))
Show the rate of a counter with one series for each host over time, displaying the rate as events per minute:
timeChart(host, function=counterAsRate(counter), unit="1/sec to 1/min")