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(). Note,
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 to get a rate.
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.
Function Traits: Aggregate
| Parameter | Type | Required | Default | Description |
|---|---|---|---|---|
as | string | optional | _rate | Name of output field. |
field[a] | string | required | Field from which to extract a number and over which to calculate rate. | |
The parameter name for field can be omitted; the following forms are equivalent:
counterAsRate("value")and:
counterAsRate(field="value")countasrate() 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")