BUG: Migrating workflows with columnar backend.

I’ll post this in case anyone else has the same issue and so that the KNIME developers can consider mitigations to prevent others having problems.

Background

  1. I have one KNIME machine with the Columnar Backend extension and I develop a workflow using the columnar backend.
  2. I export that workflow.
  3. I have a second KNIME machine without the Columnar Backend extension. I run the workflow and it completes successfully.
  4. I try to save the workflow on the second KNIME machine and get errors and I am unable to save the workflow (see attached log file).

KNIME_Log_extract.txt (4.3 KB)

Note: The same behaviour can be demonstrated if a workflow is developed using the columnar backend on one machine. The workflow saved. The Columnar Extensions are uninstalled. Then KNIME restarted, the workflow loaded and reset (all nodes). Then an attempt is made to save the workflow.

Mitigation

Installing the Columnar Extension on the second KNIME setup fixes the problem and allows the workflow to be saved.

Desired Actions

When a workflow created using the Columnar Backend is exported and imported to a second KNIME machine without the Columnar Extension:

  1. Either warn users that the workflow was developed using the columnar backend . Therefore, either warn the users that the workflow cannot be saved; or, prompt the user to install the Columnar extension.
  2. Change the behaviour of KNIME such that when a workflow developed with the columnar backend is imported to a machine without the columnar backend the nodes are updated so that the workflow can be saved.
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Hi @DiaAzul

Thanks a lot for the feedback and the suggestions!
I can reproduce this behavior and totally agree that the current state is not ideal.
I have opened a ticket for that (internal reference: AP-19695) and will keep you posted.

Cheers,
Alice

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Hi @DiaAzul

Now I can really confirm you, that bug has been fixed and the improvement will be released with 4.7 beginning of December. Thanks again a lot for your helpful suggestion and your superb specification of the problem and what you would have expected!

Have a nice weekend! :slight_smile:

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