The results calculated by irate are different.

[Mr-Lee-long]

What did you do?

this is my expression: irate(node_cpu_seconds_total{cpu="0", env="product", instance="10.43.2.64", job="product_node-exporter", meta_consul_service_port="9100", mode="iowait", tags="kubernetes-nodes"}[1m])

i clicked the execute button in the 30s, and i got three different trend results.
and i only have one single data，no copy, no slave or multiple masters.

What did you expect to see?

I think the result should be the same every time, or much the same。

What did you see instead? Under which circumstances?

1、Most of the time like this.

2、sometime like this.

3、and like this.

System information

centos7.8 3.10.0-1160.99.1.el7.x86_64

Prometheus version

2.51.1

Prometheus configuration file

- job_name: '{{ ENV }}_node-exporter'
      scrape_interval: 30s
      honor_labels: true
      consul_sd_configs:
        - server: 'http://consul-svc.monitor.svc.cluster.local:8500'
          services: ["{{ ENV }}_node-exporter"]
      relabel_configs:
            - source_labels: [__meta_consul_tags]  #p05,kubenets_nodes
              separator: ;
              regex: \,(.*?)\,(.*)\,
              target_label: tags
              replacement: ${2}
              action: replace
            - source_labels: [__meta_consul_tagged_address]
              separator: ;
              regex: (.*)
              target_label: meta_consul_tagged_address
              replacement: ${1}
              action: replace
            - source_labels: [__meta_consul_metadata]
              separator: ;
              regex: (.*)
              target_label: meta_consul_metadata
              replacement: ${1}
              action: replace
            - source_labels: [__meta_consul_service_address]
              target_label: instance
            - source_labels: [instance]
              separator: ;
              regex: (xxx)
              action: drop
            - source_labels: [__meta_consul_service_metadata]
              separator: ;
              regex: (.*)
              target_label: meta_consul_service_metadata
              replacement: ${1}
              action: replace
            - source_labels: [__meta_consul_service_port]
              separator: ;
              regex: (.*)
              target_label: meta_consul_service_port
              replacement: ${1}
              action: replace
            - source_labels: [__meta_consul_service]
              separator: ;
              regex: (.+)-(.+)
              target_label: env
              replacement: ${1}
              action: replace
            - source_labels: [__meta_consul_service]
              separator: ;
              regex: (.+)_(.+)
              target_label: env
              replacement: ${1}
              action: replace

Alertmanager version

No response

Alertmanager configuration file

No response

Logs

No response

[roidelapluie]

It looks like your graph might not be capturing all the values because the step interval (the interval between two points) could be longer than 30 seconds. This means you might miss some data points sometimes. Using the irate() function can be a bit tricky in this case because it only looks at the last two points in your selected time range, which can change a lot if you're missing some steps.

A better approach would be to use the rate() function over a longer period, like 5 minutes (rate()[5m]). This will give you a more stable and reliable measurement by averaging out more data points.

[Mr-Lee-long]

谢谢你的回答，不过这几种结果差别太大了，我把采集时间改成20s后，有很大改善。但这并没有解决我的问题。