irate_right()

Since 1.3.0

Calculate the instantaneous rate of change at the right, or latest, edge of a counter aggregate. This is equal to the last value minus the second-last value, divided by the time lapse between the two points, after accounting for resets. This calculation is useful for fast-moving counters.

Samples

Get the instantaneous rate of change at the end of each 15-minute counter aggregate.

SELECT
    id,
    bucket,
    irate_right(summary)
FROM (
    SELECT
        id,
        time_bucket('15 min'::interval, ts) AS bucket,
        counter_agg(ts, val) AS summary
    FROM foo
    GROUP BY id, time_bucket('15 min'::interval, ts)
) t

Arguments

The syntax is:

irate_right(
  summary CounterSummary
) RETURNS DOUBLE PRECISION

Name	Type	Default	Required	Description
summary	CounterSummary	-	✔	A counter aggregate created using counter_agg

Returns

Column	Type	Description
irate_right	DOUBLE PRECISION	The instantaneous rate of change at the right, or latest, edge of the counter aggregate