Describe the problem/error/question
I use a trigger that executes two MongoDB queries — both queries complete successfully and return data (sometimes different quantities, sometimes the same amount).
I then want to perform an inner join of these two results based on specific fields using the Merge node.
When I manually press Test Step on each node individually in sequence, everything works fine — the data is merged correctly.
However, when I execute the workflow fully (using Test Workflow on the trigger node), the two MongoDB requests run, but once they hit the Merge node, it shows “no data to output.”
Strangely, if I open the Merge node afterwards, click Test Step with the available data (from that same execution), the merging works perfectly — the merged data is output correctly.
In short:
Test Stepmanually → worksTest Workflowfull run → Merge node reports empty output
What is the error message (if any)?
There is no error message — just no data output from the Merge node.
Please share your workflow
MongoDB User Node Data:
[
{
"_id": "681048c63c1170aac69983ef",
"email": "[email protected]"
}
]
MongoDB OnboardingResponse Data:
[
{
"userId": "681048c63c1170aac69983ef"
}
]
Share the output returned by the last node
When running via Test Workflow, the Merge node output is empty — this is the problem!
When manually testing the Merge node with available input, it merges successfully as expected.
Debug info
core
- n8nVersion: 1.88.0
- platform: docker (self-hosted)
- nodeJsVersion: 20.19.0
- database: sqlite
- executionMode: regular
- concurrency: -1
- license: enterprise (production)
- consumerId: 8cfefd9b-f0a9-4dfe-88a9-88e7d2a5b0d3
storage
- success: all
- error: all
- progress: false
- manual: true
- binaryMode: memory
pruning
- enabled: true
- maxAge: 336 hours
- maxCount: 10000 executions
client
- userAgent: mozilla/5.0 (macintosh; intel mac os x 10_15_7) applewebkit/537.36 (khtml, like gecko) chrome/135.0.0.0 safari/537.36
- isTouchDevice: false
Generated at: 2025-04-29T04:37:24.431Z
