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

• Aggregate

• Numeric

• Time

• Window

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.