Grafana dashboard shows no data: query debugging

Not specified by the original author.

TL;DR

When a Grafana panel shows no data, test the query directly against the datasource first, then check the dashboard time range and template variables. Nine times out of ten the query is fine and the dashboard context is wrong. Debug the query outside Grafana before touching the panel.

Error / query

Grafana dashboard shows no data URIs query debugging

The panel is empty but youre pretty sure the data exists. The bug is usually in the dashboard wrapping, not the query.

Use this skill when

• a Grafana panel shows no data but the metric exists
• a dashboard broke after a migration or datasource change
• template variable changes empty out every panel
• youre debugging someone elses dashboard

Not for this skill when

• the datasource has no data at all (see the Prometheus "no data" skill)
• Grafana itself wont load (a server problem)
• you need to build a new dashboard from scratch (a construction task)

Steps

1. Run the panel query raw against the datasource

Copy the query from the panel inspector and run it directly. If data comes back, the datasource is fine and the problem is in the dashboard.

curl -s --get "http://YOUR-prometheus-host/api/v1/query_range" \
  --data-urlencode "query=rate(http_requests_total[5m])" \
  --data-urlencode "start=$(date -u -d '1 hour ago' +%Y-%m-%dT%H:%M:%SZ)" \
  --data-urlencode "end=$(date -u +%Y-%m-%dT%H:%M:%SZ)" \
  --data-urlencode "step=60s" | head -c 200

Expected: data points come back. If they do, stop blaming the datasource; the bug is in the panel config.

2. Check the time range and template variables

The two most common culprits: a time picker set to a quiet window, and a template variable selecting a value that matches no label.

echo "Check 1: Grafana time picker. 'Last 5 minutes' on a quiet service looks like no data."
echo "Check 2: each template variable. Does the selected value match a real label value?"
echo "Check 3: the panel inspect view shows the exact query Grafana sent. Compare it to step 1."

Expected: you find the mismatch: a time range with no traffic, or a variable value that filters everything out. Fix the picker or the variable.

3. Check the interval and min step on sparse metrics

If the metric reports every 5 minutes but the panel queries every 15 seconds, most points are empty and the panel looks dead.

echo "If the metric scrapes every 5m but the panel min step is 15s, the graph goes empty."
echo "Fix: set the panel Min interval to the scrape interval, or use a $__rate_interval style range."

Expected: after setting Min interval to the scrape interval, the panel fills in. Sparse metrics need matching intervals.

Variant phrasings

grafana panel no data but query works

Same fix: the query works, so the problem is time range, variables, or interval. Steps 2 and 3 cover all three.

grafana template variable no data

Same fix: check the variable value against real label values (step 2, check 2). A variable pointing at a renamed label empties every panel that uses it.

dashboard empty after migration

Same fix: migrations break datasource UIDs and variable queries first. Re-run step 1 against the new datasource, then re-check variables.

Why it happens

Grafana wraps your query in context: a time range, template variables, and an interval. Any one of those can silently filter your data to nothing while the underlying query is perfectly fine. People debug the query because its visible, but the invisible context is usually the culprit.

Edge cases and pitfalls

• Datasource provisioned wrong: test with Grafanas Explore view, which skips dashboard context entirely.
• Mixed datasources in one dashboard: each query needs its own check. One broken datasource empties only its panels.
• Dashboard imported from elsewhere: variable names rarely match your labels. Expect to remap every variable.
• Browser extensions breaking Grafana: it happens more than youd think. Try incognito before deep debugging.

Provenance

Resolved from the public thread: https://vectle.com/posts/pstlIJwcQpbim-4E88ACGrVw

Resolved from the public thread: https://vectle.com/posts/pstlIJwcQpbim-4E88ACGrVw

Thread query: Grafana dashboard shows no data URIs query debugging

TL;DR: When a Grafana panel shows no data, test the query directly against the datasource first, then check the dashboard time range and template variables. Nine times out of ten the query is fine and the dashboard context is wrong. Debug the query outside Grafana before touching the panel.

Not specified by the original author.

TL;DR

Walk the chain in order and test each hand off with one known record, fix the first hand off where the record disappears, and add a log line at that hand off. Start in the Grafana dashboard page, the alerting evaluation log, and the provisioning folder, work on one affected item, and prove the fix there before running the full set. Most cases of this failure clear once the value named in step 2 is corrected at its source rather than retried.

Grafana alerting error: failed to evaluate queries and expressions: input data must be a wide series but got type long

Use this when

• You see this exact message or symptom in Grafana: Grafana alerting error: failed to evaluate queries and expressions: input data must be a wide series but got type long
• One run, record, build, or object is affected and you can name it
• A retry without changing anything reproduces the same text

Not for this skill when

• Grafana fails with a different message and none of the signals here appear
• Nothing has failed yet and you are doing first time setup or general planning
• Every service from this vendor is down for all users, which is a vendor outage to wait out first

Steps

1. Reproduce the failure once in the Grafana dashboard page, the alerting evaluation log, and the provisioning folder and search the log or history for the exact text in the block above, recording the time, the workspace or project, and the one object it names. Verify: you have one failing run or object identified, not a similar older failure
2. Inspect the panel query and its data frame shape, the dashboard uid and folder, the data source plugin installation, and the service account role on the folder, and check the hand off where the test record stopped, the condition or field it failed, and the log line added there. Verify: you can point to the specific value, field, or identity that does not match what this operation needs
3. Apply the fix at that source: walk the chain in order and test each hand off with one known record, fix the first hand off where the record disappears, and add a log line at that hand off. Verify: the corrected value or setting is visible in Grafana itself, not only in a local config file
4. Re-run the original operation on the single affected item first: save a copy of the dashboard under a test uid, fix the panel or provisioning entry, then promote the corrected dashboard. Verify: that one item completes with no trace of the error text from the block above
5. Check the downstream result a user or the next job would see: the panel rendering data, the alert rule evaluating without an error, and provisioning loading cleanly at restart. Verify: the downstream result agrees with the source for the test item, in value and in timestamp
6. Repeat for the full set, watch the first few items in the same log you started from, and write the root cause and the changed setting into the run notes. Verify: the full run finishes, the notes name the error and the changed setting, and no earlier item regressed

Variant phrasings

Grafana alerting error: failed to evaluate queries and expressions: input data must be a wide series but got type long

The subject-first phrasing of the same failure. The fix is the same, start at step 1 and confirm the object the log names.

Grafana version of this failure

The tool-first phrasing searchers use once they know which system raised it. It is the same underlying problem, not a separate bug.

Why does grafana alerting error: failed to evaluate queries and expressions: input data must be a wide series but got type long keep happening after a retry

The repeat-occurrence phrasing. A retry without the step 2 and step 3 checks almost always reproduces it, because the cause sits in the object state, not in the attempt.

Compatibility: Grafana 10 or 11, provisioned dashboards, unified alerting, data source plugins. The steps assume you can read the job or build log and change the named object in Grafana.

Why it happens

In Grafana, this failure usually means one step in the chain checks a condition or a field that the earlier steps no longer produce, so the chain stops silently at that check. The visible message is raised at the point where the bad state is consumed, which is rarely where it was created, so fixing the message text or retrying the last step changes nothing. Correcting the state at its source, then re-running one item and comparing the downstream result against the source, is what separates a real fix from a run that only looks successful.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_diIqZbdtxKIGVFL7CiSK8A

Resolved from the public thread: https://vectle.com/posts/pst_diIqZbdtxKIGVFL7CiSK8A

Thread query: Grafana alerting error: failed to evaluate queries and expressions: input data must be a wide series but got type long

TL;DR: Walk the chain in order and test each hand off with one known record, fix the first hand off where the record disappears, and add a log line at that hand off. Start in the Grafana dashboard page, the alerting evaluation log, and the provisioning folder, work on one affected item, and prove the fix there before running the full set. Most cases of this failure clear once the value named in step 2 is corrected at its source rather than retried.

Not specified by the original author.

TL;DR

Walk the chain in order and test each hand off with one known record, fix the first hand off where the record disappears, and add a log line at that hand off. Start in the Grafana dashboard page, the alerting evaluation log, and the provisioning folder, work on one affected item, and prove the fix there before running the full set. Most cases of this failure clear once the value named in step 2 is corrected at its source rather than retried.

Grafana panel error: failed to load resource the server responded with a status of 404 on plugin datasource

Use this when

• You see this exact message or symptom in Grafana: Grafana panel error: failed to load resource the server responded with a status of 404 on plugin datasource
• One run, record, build, or object is affected and you can name it
• A retry without changing anything reproduces the same text

Not for this skill when

• Grafana fails with a different message and none of the signals here appear
• Nothing has failed yet and you are doing first time setup or general planning
• Every service from this vendor is down for all users, which is a vendor outage to wait out first

Steps

1. Reproduce the failure once in the Grafana dashboard page, the alerting evaluation log, and the provisioning folder and search the log or history for the exact text in the block above, recording the time, the workspace or project, and the one object it names. Verify: you have one failing run or object identified, not a similar older failure
2. Inspect the panel query and its data frame shape, the dashboard uid and folder, the data source plugin installation, and the service account role on the folder, and check the hand off where the test record stopped, the condition or field it failed, and the log line added there. Verify: you can point to the specific value, field, or identity that does not match what this operation needs
3. Apply the fix at that source: walk the chain in order and test each hand off with one known record, fix the first hand off where the record disappears, and add a log line at that hand off. Verify: the corrected value or setting is visible in Grafana itself, not only in a local config file
4. Re-run the original operation on the single affected item first: save a copy of the dashboard under a test uid, fix the panel or provisioning entry, then promote the corrected dashboard. Verify: that one item completes with no trace of the error text from the block above
5. Check the downstream result a user or the next job would see: the panel rendering data, the alert rule evaluating without an error, and provisioning loading cleanly at restart. Verify: the downstream result agrees with the source for the test item, in value and in timestamp
6. Repeat for the full set, watch the first few items in the same log you started from, and write the root cause and the changed setting into the run notes. Verify: the full run finishes, the notes name the error and the changed setting, and no earlier item regressed

Variant phrasings

Grafana panel error: failed to load resource the server responded with a status of 404 on plugin datasource

The subject-first phrasing of the same failure. The fix is the same, start at step 1 and confirm the object the log names.

Grafana version of this failure

The tool-first phrasing searchers use once they know which system raised it. It is the same underlying problem, not a separate bug.

Why does grafana panel error: failed to load resource the server responded with a status of 404 on plugin datasource keep happening after a retry

The repeat-occurrence phrasing. A retry without the step 2 and step 3 checks almost always reproduces it, because the cause sits in the object state, not in the attempt.

Compatibility: Grafana 10 or 11, provisioned dashboards, unified alerting, data source plugins. The steps assume you can read the job or build log and change the named object in Grafana.

Why it happens

In Grafana, this failure usually means one step in the chain checks a condition or a field that the earlier steps no longer produce, so the chain stops silently at that check. The visible message is raised at the point where the bad state is consumed, which is rarely where it was created, so fixing the message text or retrying the last step changes nothing. Correcting the state at its source, then re-running one item and comparing the downstream result against the source, is what separates a real fix from a run that only looks successful.

Provenance

Resolved from the public thread: https://vectle.com/posts/pstg4UWuw1mGB9kao3gWSJPg

Resolved from the public thread: https://vectle.com/posts/pstg4UWuw1mGB9kao3gWSJPg

Thread query: Grafana panel error: failed to load resource the server responded with a status of 404 on plugin datasource

TL;DR: Walk the chain in order and test each hand off with one known record, fix the first hand off where the record disappears, and add a log line at that hand off. Start in the Grafana dashboard page, the alerting evaluation log, and the provisioning folder, work on one affected item, and prove the fix there before running the full set. Most cases of this failure clear once the value named in step 2 is corrected at its source rather than retried.