Calculate the instantaneous rate of change at the left, or earliest, edge of a counter aggregate. This is equal to the second value minus the first value, divided by the time lapse between the two points, after accounting for resets. This calculation is useful for fast-moving counters.
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| language |
code |
sql |
irate_left(
summary CounterSummary
) RETURNS DOUBLE PRECISION
|
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|
| required |
returns |
| name |
type |
description |
summary |
CounterSummary |
A counter aggregate created using [`counter_agg`](#counter_agg) |
|
|
| column |
type |
description |
idelta_left |
DOUBLE PRECISION |
The instantaneous rate of change at the left, or earliest, edge of the counter aggregate |
|
|
|
| description |
command |
Get the instantaneous rate of change at the start of each 15-minute counter aggregate. |
| code |
SELECT
id,
bucket,
irate_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
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