-
What Grafana version and what operating system are you using?
Grafana 10.0.2 (running in k3s, browsing through recent Chrome on Arch Linux, as well as an very outdated Chrome on a very outdated Nexus10 tablet - but I’m pretty sure it’s not a client issue) -
What are you trying to achieve?
This might sound like a weird one, since it’s basically one of the main use cases for the Stat panel, as far as I can understand - but it doesn’t behave like expected for me:
I want to show the most recent value of some metric queried from a Prometheus data source, like the current temperature (query: avg(homeassistant_sensor_temperature_celsius{entity="sensor...."}) or if my internet connection is up (query: min(probe_success{target="google-tcp"})), while also having the sparkline to see the current trend and recent history.
This is displayed on a dashboard refreshing every 5s and a 24h range, from now.
- How are you trying to achieve it?
I created a Stat panel using default options (Prometheus range query, graphing the sparkline, no adjustment to data points, using either Last or Last* as calculation method), which seemed to work fine at first.
After noticing that all my Stat panels lag behind a couple of minutes when displayed on my dashboard (but not during query building in Explore!), I dug a bit deeper and realized that the last datapoint received by my query isn’t the most recent one (especially in a tiny panel for a 24h range), but up to two intervals to the left; I guess that’s how Prometheus distributes its datapoints?
As a bad workaround, I used the query options in my panel to increase max datapoints to some absurd value (99999 for good measure), to get the step down to a minimum of 5s.
While this works fine enough, I’m requesting a very detailed resolution, only to graph it in a small area and printing the most recent value from it. Since my Prometheus is running on a Raspberry Pi, I want to keep it light and simple.
Then I learned about the difference between Range and Instant queries - since I want to see the Instant value on top of a ranged sparkline, I thought Both would be ideal…
- What happened?
Stat panel can’t seem to merge Both queries, but displaying two Stats - one for the Range result, one for Instant:
Not sure if Both queries are even supposed to be there - at least for Alerting, I found an issue about migrating Both to Range.
It’s even more interesting with a simple time() * 1000 query, since it’s also showing my issue with the range query not getting the most recent value:
Put together on a dashboard (config see below - “Instant being up to date, but now supporting sparkline” should say “Instant being up to date, but not supporting sparkline”):
- What did you expect to happen?
Without knowing anything, I’d expect it to just work - always showing me the instant value over the sparkline.
After thinking about data points, steps and intervals, I see why that might not be possible with a Range query, but wouldn’t expect more than one interval of delay - in my example building the query, I have a interval and min step of 5s, but getting a difference of 9s between Range and Instant.
And last but not least, I would expect Both to solve my issue, appending the Instant result to the Range one, so only one Stat is shown in the panel - instead of treating them as two completely seperate queries/results/metrics.
- Can you copy/paste the configuration(s) that you are having problems with?
dashboard.json
{
"annotations": {
"list": [
{
"builtIn": 1,
"datasource": {
"type": "grafana",
"uid": "-- Grafana --"
},
"enable": true,
"hide": true,
"iconColor": "rgba(0, 211, 255, 1)",
"name": "Annotations & Alerts",
"type": "dashboard"
}
]
},
"editable": true,
"fiscalYearStartMonth": 0,
"graphTooltip": 0,
"links": [],
"liveNow": false,
"panels": [
{
"datasource": {
"type": "prometheus",
"uid": "prometheus"
},
"fieldConfig": {
"defaults": {
"color": {
"mode": "thresholds"
},
"mappings": [],
"thresholds": {
"mode": "absolute",
"steps": [
{
"color": "green",
"value": null
},
{
"color": "red",
"value": 80
}
]
},
"unit": "dateTimeAsLocalNoDateIfToday"
},
"overrides": []
},
"gridPos": {
"h": 8,
"w": 12,
"x": 0,
"y": 0
},
"id": 1,
"options": {
"colorMode": "value",
"graphMode": "area",
"justifyMode": "auto",
"orientation": "auto",
"reduceOptions": {
"calcs": [
"lastNotNull"
],
"fields": "",
"values": false
},
"textMode": "auto"
},
"pluginVersion": "10.0.2",
"targets": [
{
"datasource": {
"type": "prometheus",
"uid": "prometheus"
},
"editorMode": "code",
"expr": "time() * 1000",
"instant": false,
"range": true,
"refId": "A"
}
],
"title": "Ranged lagging behind",
"type": "stat"
},
{
"datasource": {
"type": "prometheus",
"uid": "prometheus"
},
"fieldConfig": {
"defaults": {
"color": {
"mode": "thresholds"
},
"mappings": [],
"thresholds": {
"mode": "absolute",
"steps": [
{
"color": "green",
"value": null
},
{
"color": "red",
"value": 80
}
]
},
"unit": "dateTimeAsLocalNoDateIfToday"
},
"overrides": []
},
"gridPos": {
"h": 8,
"w": 12,
"x": 12,
"y": 0
},
"id": 2,
"interval": "1s",
"maxDataPoints": 1000000,
"options": {
"colorMode": "value",
"graphMode": "area",
"justifyMode": "auto",
"orientation": "auto",
"reduceOptions": {
"calcs": [
"lastNotNull"
],
"fields": "",
"values": false
},
"textMode": "auto"
},
"pluginVersion": "10.0.2",
"targets": [
{
"datasource": {
"type": "prometheus",
"uid": "prometheus"
},
"editorMode": "code",
"expr": "time() * 1000",
"instant": false,
"range": true,
"refId": "A"
}
],
"title": "Ranged with 1000000 datapoints to get a claimed interval of 1s (still lags behind!)",
"type": "stat"
},
{
"datasource": {
"type": "prometheus",
"uid": "prometheus"
},
"fieldConfig": {
"defaults": {
"color": {
"mode": "thresholds"
},
"mappings": [],
"thresholds": {
"mode": "absolute",
"steps": [
{
"color": "green",
"value": null
},
{
"color": "red",
"value": 80
}
]
},
"unit": "dateTimeAsLocalNoDateIfToday"
},
"overrides": []
},
"gridPos": {
"h": 8,
"w": 12,
"x": 0,
"y": 8
},
"id": 4,
"options": {
"colorMode": "value",
"graphMode": "area",
"justifyMode": "auto",
"orientation": "auto",
"reduceOptions": {
"calcs": [
"lastNotNull"
],
"fields": "",
"values": false
},
"textMode": "auto"
},
"pluginVersion": "10.0.2",
"targets": [
{
"datasource": {
"type": "prometheus",
"uid": "prometheus"
},
"editorMode": "code",
"exemplar": false,
"expr": "time() * 1000",
"instant": true,
"range": false,
"refId": "A"
}
],
"title": "Instant being up to date, but now supporting sparkline",
"type": "stat"
},
{
"datasource": {
"type": "prometheus",
"uid": "prometheus"
},
"fieldConfig": {
"defaults": {
"color": {
"mode": "thresholds"
},
"mappings": [],
"thresholds": {
"mode": "absolute",
"steps": [
{
"color": "green",
"value": null
},
{
"color": "red",
"value": 80
}
]
},
"unit": "dateTimeAsLocalNoDateIfToday"
},
"overrides": []
},
"gridPos": {
"h": 8,
"w": 12,
"x": 12,
"y": 8
},
"id": 3,
"options": {
"colorMode": "value",
"graphMode": "area",
"justifyMode": "auto",
"orientation": "auto",
"reduceOptions": {
"calcs": [
"lastNotNull"
],
"fields": "",
"values": false
},
"textMode": "auto"
},
"pluginVersion": "10.0.2",
"targets": [
{
"datasource": {
"type": "prometheus",
"uid": "prometheus"
},
"editorMode": "code",
"exemplar": false,
"expr": "time() * 1000",
"instant": true,
"range": true,
"refId": "A"
}
],
"title": "Instant being up to date, but now supporting sparkline",
"type": "stat"
}
],
"refresh": "",
"schemaVersion": 38,
"style": "dark",
"tags": [],
"templating": {
"list": []
},
"time": {
"from": "now-7d",
"to": "now"
},
"timepicker": {},
"timezone": "",
"title": "New dashboard",
"version": 0,
"weekStart": ""
}
Am I misunderstanding anything major, is this just not supported, or the Stat panel not being able to render Both queries a bug?
