What Grafana version and what operating system are you using?
Grafana v11.6.8
What are you trying to achieve?
I have a dashboard panel using the built-in Bar Chart visualization, backed by a custom data source, that should refresh and redraw with new data on every dashboard refresh (auto-refresh or manual).
How are you trying to achieve it?
Panel type: barchart
Field color mode: tried multiple options — “By series”, “Classic palette”, “Continuous” — as well as “From thresholds (by value)”
Data source returns a fresh set of values on each query (time-bucketed metric data, values change per refresh)
Dashboard auto-refresh enabled (also tested with manual refresh)
What happened?
The Bar Chart panel intermittently stops updating visually on refresh. The panel inspector’s “Query”/“JSON” tabs confirm the data source is returning new/updated values, but the rendered bars stay stale (or blank) — as if the chart never redrew.
The chart only starts rendering the latest data again after forcing the panel to remount — e.g., switching the panel to Table view and then switching back to Bar chart view. A plain data refresh alone does not trigger the redraw.
Critically, this only happens when the field color mode is not “From thresholds (by value)”. When color mode is set to “From thresholds (by value)”, the panel redraws correctly on every refresh, no toggle needed. With other color modes (“By series”, “Classic palette”, “Continuous”), the panel silently fails to redraw and requires the table-view toggle workaround.
What did you expect to happen?
The Bar Chart panel should re-render with the latest query data on every refresh, regardless of which field color mode is configured.
Can you copy/paste the configuration(s) that you are having problems with?
Did you receive any errors in the Grafana UI or in related logs? If so, please tell us exactly what they were.
No errors are shown in the UI or browser console; the panel simply fails to redraw silently. No related error entries observed in Grafana server logs either.
Did you follow any online instructions? If so, what is the URL?
No — this was found through internal testing/support triage, not from following an online guide.
This appears to be a Bar Chart rendering/redraw issue, rather than a query refresh issue. The panel is receiving the updated data, but the visualization is not consistently redrawing it.
As a workaround, set Standard options → Color scheme → From thresholds (by value). Based on your testing, this mode redraws correctly after each refresh.
If you need to keep the other color modes, switching the visualization to Table and then back to Bar Chart causes the latest data to render, but this is only a workaround.
It would also be useful to test the same panel with Grafana’s TestData datasource. If the issue reproduces there, it would further indicate that the problem is in the Bar Chart visualization rather than the custom datasource.
