How can I sort the legend by series name in Prometheus/Grafana

Question

I have a Grafana dashboard panel configured to render the results of a Prometheus query. There are a large number of series returned by the query, with the legend displayed to the right. If the user is looking for a specific series, they have to potentially scroll through all of them, and it's easy to miss the one they're looking for. So I'd like to sort the legend by series name, but I can't find any way to do that.

My series name is a concatenation of two labels, so if I could sort the instant vector returned from the PromQL query by label value, I think Grafana would use that order in the legend. But I don't see any way to do that in Prometheus. There is a sort() function, but it sorts by sample value. And I don't see any way to sort the legend in Grafana.

Carman

Answer 1

As far as I know, You can only use the function sort() to sort metrics by value.

• According to this PR, Prometheus does not intend to provide the function sort_by_label().
• According to this Issue, Grafana displays the query results from Prometheus without sorting.
• According to this Issue, Grafana supports sorting by value when displaying legend.

In Grafana 7, Prometheus metrics can be transformed from time series format to table format using the Transform module, so that you can sort the metrics by any label or value.

---

In December 2023, prometheus v2.49 finally added sort_by_label() and sort_by_label_desc()

Diplo

So after I have used a Transform to get a table, how do I choose which columns of the table I want to sort on? – Cantillate

Just like a regular table, you can click on the column name of the table and it will be sorted in ascending or descending order. In addition, Transform supports changing column names, filtering, and calculating statistics. – Diplo

The position of the prom maintainers seems to have softened a bit and you might get lucky in the future with the following PR github.com/prometheus/prometheus/pull/11299 – Erfurt

It has been merged! – Nudnik

Answer 2

Prometheus doesn't support sorting results by series names as mentioned in https://mcmap.net/q/727865/-how-can-i-sort-the-legend-by-series-name-in-prometheus-grafana . If you still need sorting results by metric name or by arbitrary set of labels, then take a look at VictoriaMetrics. It provides sort_by_label and sort_by_label_desc functions. For example, the following query sorts time series returned by query by metric names:

sort_by_label(query, "__name__")

The __name__ refers to metric name. See these docs for more details.

Serviceberry

VictoriaMetrics is 100% retro-compatible with Prometheus but (IMHO) with superior quality-of-life improvements such as this. =) – Gracia