How to avoid "vector cannot contain metrics with the same labelset" error when plotting rate() from several metrics (same labelset, different names)

user_1759063 0
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In Prometheus sometimes we need to plot several metrics at onces (say, having name, fitting the same regex) like that PromQL query:

{name=~"camel_proxy.*count"}

and it works fine, the same labelset lines are plotted with the different names.

When we want to plot the rate() of them, we face the error from the title:

rate({name=~"camel_proxy.*count"}[5m])

So, the way here is to make labelset not the same, and to move the __name__ to some label, making each labelset to be unique:

rate(label_replace({name=~"camel_proxy.*count"},"name_label","$1","name", "(.+)")[5m])

But we are still getting the error like

1:90: parse error: ranges only allowed for vector selectors"

How to avoid it and plot the rates correctly?

grafana prometheus promql
2 Answers

The PromQL query here should be

rate(label_replace({name=~"camel_proxy.*count"},"name_label","$1","name", "(.+)")[5m:])

please note 5m**:** instead of 5m

user_17590630

The label_replace() inside rate() triggers subquery processing, which may return unexpected results, since the rate() starts working with calculated samples returned from label_replace() instead of raw samples stored in the database.

MetricsQL at VictoriaMetrics (this is Prometheus-like monitoring solution I work on) provides more elegant solution for vector cannot contain metrics with the same labelset error - keep_metric_names modifier. Just put this modifier after the function, which strips metric names, in order to instruct it to keep metric names:

rate({name=~"camel_proxy.*count"}[5m]) keep_metric_names

This solution avoids triggering subquery processing, so the rate() function continues working on raw samples stored in the database.

user_2749370
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