counter_zero_time()

Since 1.3.0

Calculate the time when the counter value is predicted to have been zero. This is the x-intercept of the linear fit between counter value and time.

Samples

Estimate the time when the counter started

SELECT
    id,
    bucket,
    counter_zero_time(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:

counter_zero_time(
    summary CounterSummary
) RETURNS TIMESTAMPTZ

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

Returns

Column	Type	Description
counter_zero_time	TIMESTAMPTZ	The time when the counter value is predicted to have been zero