Functions

delta()

delta(v range-vector) calculates the difference between the first and last value of each time series element in a range vector v, returning an instant vector with the given deltas and equivalent labels

delta(cpu_temp_celsius{host="zeus"}[2h])

increase()

increase(v range-vector) calculates the increase in the time series in the range vector

increase(http_requests_total{job="api-server"}[5m])

increase should only be used with counters

It is syntactic sugar for rate(v) multiplied by the number of seconds under the specified time range window, and should be used primarily for human readability. Use rate in recording rules so that increases are tracked consistently on a per-second basis.

irate()

irate(v range-vector) calculates the per-second instant rate of increase of the time series in the range vector. This is based on the last two data points

irate(http_requests_total{job="api-server"}[5m])

irate should only be used when graphing volatile, fast-moving counters. Use rate for alerts and slow-moving counters, as brief changes in the rate can reset the FOR clause and graphs consisting entirely of rare spikes are hard to read.

rate()

rate(v range-vector) calculates the per-second average rate of increase of the time series in the range vector

rate(http_requests_total{job="api-server"}[5m])

rate should only be used with counters

It is best suited for alerting, and for graphing of slow-moving counters