Stat panel showing no data when using last

Grafana Stat Panel
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1

I have a stat panel that is pulling data from an Influxdb that is being updated every 1s. It’s using this Flux query:

from(bucket: v.bucket)
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["Metric"] == "fMeasure")
  |> filter(fn: (r) => r["_field"] == "value")
  |> aggregateWindow(every: v.windowPeriod, fn: mean, createEmpty: true)

This works, I get a stat panel value and also the underlying graph:

image

As soon as I change the calculation from ‘last value’ to ‘last non-null value’ I start to get flashes of ‘no data’.

If I switch the stat panel to a line graph and look at the underlying data I have no blank periods so I know the data is there.

There’s 3 stats/graphs (not sure how to word this) in the panel and it is always the right hand two that flash up ‘no data’. It feels like it could be a processing performance thing, rather than a lack of data? i.e. it processes the stat graphs from left to right and it’s always the right hand graphs that seem to have an issue.

Any thoughts?

2

Does changing the aggregateWindow function to this change anything?

  |> aggregateWindow(every: v.windowPeriod, fn: last, createEmpty: false)
3

Hi @grant2

Sadly not, but whilst playing around it seems that if I remove the aggregation line entirely, everything is fine.

The current query:

from(bucket: v.bucket)
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["Metric"] == "fMeasure")
  |> filter(fn: (r) => r["_field"] == "value")

Looking at the stats, the new query takes 20ms longer and pulls in 250 more points, but everything seems to be handling it.

Is there an aggregation option I’m missing?

4

Sometimes (esp. when your data range is short, or sparsely populated) you do not need the aggregateWindow() function. Are you displaying the Stat Panels to cover a wide range of time? You mentioned that data is being added every 1s, so if you wanted a range of, say, 1 day, that’s a lot of “unaggregated” data.

5

Hi,

It’s a 1hr period being displayed.