`percentile`

Description

Returns the approximate n-th percentile of a numerical expression.

The percentile value must be between 0 and 1.
The calculation is approximate, with accuracy controlled by the optional error_threshold.

Syntax

percentile(percentile: number, expression: number, error_threshold: number?): number

Arguments

Name	Type	Required	Description
percentile	number	true	Percentile to compute, between `0` and `1`
expression	number	true	Numerical expression whose percentile is calculated
error_threshold	number	false	Accuracy of approximation. Lower values are more accurate but slower. Defaults to `0.01`

Example

Use case: Calculate the 99th percentile of trace durations

Suppose you want to compute the 99th percentile latency for Lambda function invocations.

Example data

{ "operationName": "Lambda.Invoke", "duration": 95000 },
{ "operationName": "Lambda.Invoke", "duration": 500000 },
{ "operationName": "Lambda.Invoke", "duration": 1100000 },
{ "operationName": "Lambda.Invoke", "duration": 1482000 },
{ "operationName": "CheckoutFlow", "duration": 800000 }

Example query

source spans
| filter $l.operationName == 'Lambda.Invoke'
| groupby $l.operationName aggregate percentile(0.99, $m.duration) as p99_latency

Example output

operationName	p99_latency
Lambda.Invoke	1482198.478333334

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