Get last value even if outside of time

Grafana InfluxDB
1

  • What Grafana version and what operating system are you using?
    v9.4.7

  • What are you trying to achieve?
    get the last value, so there is always a value displayed, even if not:

  • What happened?
    Due to API Limitations I can only fetch data very rarely. Some components does only work with “Event Polling”. So there could be the same data for a long time.

  • What did you expect to happen?
    As said, it is possible that the last entry in db is like 3 days ago, but the value never changed (i just don´t save the same value again, due to very high db usage)
    So currently, if I have the same value a long time, there is no data displayed anymore. Currently I fill in the gaps with previous or linear. But as soon as the last point is out of time I get no data display.
    My goal:
    Always have last data fillable with previous or linear even if out of time scale

  • Can you copy/paste the configuration(s) that you are having problems with?
    My query:
    SELECT mean("value") FROM "..." WHERE $timeFilter GROUP BY time($__interval) fill(previous)

2

Welcome

What is your data source?

3

What do you mean?
I use InfluxDB with Node-RED.

If it’s not what you wanted, please let me know
I am relatively new to grafana/influx

Thank you

1 Like
4

Hi @vito0912,
Maybe you can just set longer time range for that specific panel like on next link?:

https://community.grafana.com/t/each-panel-has-its-own-timeline/79929/4?u=ldrascic

All other panels on that dashboard would have time range from time picker (in upper right corner).

 

Best regards,
ldrascic

5

so it looks like you are using influxql query language on influxdb. I wonder if there is a way to check the value of mean and conditionally choose the following use of last?

select last(field_1),* from measurement group by *
6

Thanks for your idea. However, this would only delay the problem and break the statisics, since a 6h view should be the case with me

7

It seems to work kind of. I modified it a little bit to work with my needs. It now finds the data (the % at top right is shown correctly). And also shows “data outside time range”. But it doesn´t show a graph. Even when using fill(previous)

grafik
grafik1208×676 33.7 KB

F is my normal
H is “yours”

8

what does the data tab show, behind the graph

9

Thank you for this.

It seems to work OK when the time range is set to get the all last values

Example: Last 12 hours

image
image2074×625 45.7 KB

When I set the time range to Last 5 minutes or Last 1 hour Grafana will exclude all (or some) queries

image
image2043×624 41.6 KB

image
image2068×634 21.7 KB

Any solution to this?

Br,
kd

10

Best way I found so far: (in fluxDB)

Do a sort of pre-fetch by selecting a slightly larger period, using the fill(useprevious)
And then reducing te selection again to the original range.

import “date”

from(bucket: “Insights”)
|> range(start: date.sub(d: 24h, from: v.timeRangeStart), stop: v.timeRangeStop)
|> filter(fn: (r) => r[“_field”] == “measure_humidity”)
|> aggregateWindow(every: v.windowPeriod, fn: mean, createEmpty: true)
|> fill(usePrevious: true)
|> range(start: v.timeRangeStart, stop: v.timeRangeStop)
|> yield(name: “last”)

1 Like