delta#

Description#

Calculates the value difference of the argument in each time bin for each group.

delta may produce negative values when the argument decreases over time. See also delta_monotonic.

When the argument is a metric defined using set_metric, delta behaves differently according to the specified metric type:

  • for gauge metrics, delta retains the default behavior. Negatives may be produced when the value is decreasing.

  • for cumulativeCounter metrics, delta will assume the values to be monotonically increasing, and treats decreasing values as counter resets. Negatives will not be produced for cumulativeCounter type metrics.

  • for delta metrics, delta will sum up the values in the time window to return the total sum. Negatives may be produced for negative input values.

Return type#

numeric or duration

Domain#

This is an aggregate function (aggregates rows over a group in aggregate verbs.)

This is a window function (calculates over a group of multiple input rows using windowing.)

Categories#

Usage#

delta(val)

Argument

Type

Optional

Repeatable

Restrictions

val

numeric or duration

no

no

none

Examples#

align 5m, requests: delta(m("failures"))

Computes the delta of “failures” metric for each 5m time bins. The result may be positive or negative.