num_changes()

Get the number of times a counter changed from a counter aggregate

Since 1.3.0

Get the number of times the counter changed during the period summarized by the counter aggregate. Any change is counted, including resets to zero.

Samples

Get the number of times the counter changed over each 15-minute interval.

SELECT
    id,
    bucket,
    num_changes(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:

num_changes(
    summary CounterSummary
) RETURNS BIGINT

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

Returns

Column	Type	Description
num_changes	BIGINT	The number of times the counter changed