idelta_left() and idelta_right()

The instantaneous change in the counter at the left (earlier) and right (later) side of the time range.

For more information about counter aggregation functions, see the hyperfunctions documentation.

idelta_left()

The instantaneous change in the counter at the left (earlier) side of the time range. Essentially, the first value subtracted from the second value seen in the time range (handling resets appropriately). This can be especially useful for fast moving counters.

idelta_left(
    summary CounterSummary
) RETURNS DOUBLE PRECISION

Required arguments

Returns

Sample usage

SELECT
    id,
    bucket,
    idelta_left(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

idelta_right()

The instantaneous change in the counter at the right (later) side of the time range. Essentially, the penultimate value subtracted from the last value seen in the time range (handling resets appropriately). This can be especially useful for fast moving counters.

idelta_right(
    summary CounterSummary
) RETURNS DOUBLE PRECISION

Required arguments

Returns

Sample usage

SELECT
    id,
    bucket,
    idelta_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