@@ -107,7 +107,7 @@ The two approaches have a number of different implications:
...
@@ -107,7 +107,7 @@ The two approaches have a number of different implications:
|---|-----------|---------
|---|-----------|---------
| Required configuration | Pick buckets suitable for the expected range of observed values. | Pick desired φ-quantiles and sliding window. Other φ-quantiles and sliding windows cannot be calculated later.
| Required configuration | Pick buckets suitable for the expected range of observed values. | Pick desired φ-quantiles and sliding window. Other φ-quantiles and sliding windows cannot be calculated later.
| Client performance | Observations are very cheap as they only need to increment counters. | Observations are expensive due to the streaming quantile calculation.
| Client performance | Observations are very cheap as they only need to increment counters. | Observations are expensive due to the streaming quantile calculation.
| Server performance | The server has to calculate quantiles. You can use [recording rules](/docs/prometheus/latest/querying/rules/#recording-rules) should the ad-hoc calculation take too long (e.g. in a large dashboard). | Low server-side cost.
| Server performance | The server has to calculate quantiles. You can use [recording rules](/docs/prometheus/latest/configuration/recording_rules/#recording-rules) should the ad-hoc calculation take too long (e.g. in a large dashboard). | Low server-side cost.
| Number of time series (in addition to the `_sum` and `_count` series) | One time series per configured bucket. | One time series per configured quantile.
| Number of time series (in addition to the `_sum` and `_count` series) | One time series per configured bucket. | One time series per configured quantile.
| Quantile error (see below for details) | Error is limited in the dimension of observed values by the width of the relevant bucket. | Error is limited in the dimension of φ by a configurable value.
| Quantile error (see below for details) | Error is limited in the dimension of observed values by the width of the relevant bucket. | Error is limited in the dimension of φ by a configurable value.
| Specification of φ-quantile and sliding time-window | Ad-hoc with [Prometheus expressions](/docs/prometheus/latest/querying/functions/#histogram_quantile). | Preconfigured by the client.
| Specification of φ-quantile and sliding time-window | Ad-hoc with [Prometheus expressions](/docs/prometheus/latest/querying/functions/#histogram_quantile). | Preconfigured by the client.