trim_to()

Reduce the covered interval of a heartbeat aggregate

Since 1.16.0

Reduce the time range covered by a heartbeat aggregate. This can only be used to narrow the covered interval, passing arguments that would extend beyond the range covered by the initial aggregate gives an error.

Samples

Given a table called liveness containing weekly heartbeat aggregates in column health with timestamp column date, use this query to roll up several weeks and trim the result to an exact month:

SELECT trim_to(rollup(health), '03-1-2022 UTC', '1 month')
FROM liveness
WHERE date > '02-21-2022 UTC' AND date < '3-7-2022 UTC'

Arguments

The syntax is:

trim_to(
    agg HEARTBEATAGG,
    start TIMESTAMPTZ,
    duration INTERVAL
) RETURNS HEARTBEATAGG

Name	Type	Default	Required	Description
agg	HeartbeatAgg	-	✔	A heartbeat aggregate to trim down
start	TimestampTz	-		The start of the trimmed range. If not provided, the returned heartbeat aggregate starts from the same time as the starting one
duration	Interval	-		How long the resulting aggregate should cover. If not provided, the returned heartbeat aggregate ends at the same time as the starting one

Returns

Column	Type	Description
trim_to	heartbeat_agg	The trimmed aggregate.