Prometheus query to count unique label values over a period

user_18354539 0
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I want to calc the total distinct label counts over a period time.

Eg. I have below 4 sample data

Metrics Labels TimeStamp Values

cpu_usage{instance="192.168.100.10:20001",job="node2"}@1646225640 => 4
cpu_usage{instance="192.168.100.10:20001",job="node1"}@1646225700 => 5
cpu_usage{instance="192.168.100.10:20001",job="node3"}@1646225760 => 3
cpu_usage{instance="192.168.100.10:20001",job="node2"}@1646225820 => 4

So if I check startdate=1646225640, enddate=1646225700, I got 2 distinct jobs, which are node2 and node1

if I check startdate=1646225640, end date=1646225820, I got 3 distinct jobs, which are node1, node2, and node3.

Is there a way in promql can do this?

grafana prometheus
1 Answers

Find one way to achieve this

count by (job_temp) (count_over_time(cpu_usage[1h]))

or

sum(count by (job) (count_over_time(cpu_usage[1h])))

PromQL is a time-series based so I find it more useful to illustrate with image:

enter image description here

say we want to check between 1646225640 and 1646225820

prometheus data is based on metrics{labels} for a series of timestamp, so count_over_time will return results with 3 records:

instance=192.168.100.10:20001,job=node1 values=[[1646225700, 1]] instance=192.168.100.10:20001,job=node2 values=[[1646225640, 1], [1646225820, 1]] instance=192.168.100.10:20001,job=node3 values=[[1646225760, 1]]

for above results, if we count by job, it's like group by job, so we have 3 results too

if we count by labels that doesn't exist in the metrics, then prometheus will just take no label as group by filter, then we will only have 1 result cause they haven't been grouped at all, which is the second query sum method effect

user_183545390
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