Response delay percentile (P25, P50, P75, P85, P95, etc.) statistical function

[peoplewhoworkhard]

Proposal

Hello, I would like to ask whether prometheus has the function of calculating the response delay percentile (pxx), and if so, what is the algorithm used?

[beorn7]

Not sure what you mean by "response delay percentile" specifically, but there are various ways of calculating percentiles AKA quantiles in Prometheus:

• First and foremost, see https://prometheus.io/docs/practices/histograms/ to understand the Summary and the (classic) Histogram metric type. They allow you to calculate quantiles of distributions gathered by the instrumented target.
• There is also a quantile aggregation operator to calculate quantiles over dimensions.
• Finally, there is quantile_over_time to calculate quantiles over time.

Also note the new experimental Native Histograms to increase the accuracy of quantile estimations.