Try/Catch nodes do not work with Column Aggregator node fail

Hi, When using Try and Catch nodes, if I put Try before the Column Aggregator node, and Catch after the Column Aggregator node, it fails to proceed when there is an error.
So if you preconfigure the Column Aggregator node and then change the input of columns going in to the node such that it fails because there are now no columns selected for aggregation, then the node fails and the Try/Catch nodes fail to proceed.

HI @richards99 -

Can you upload a workflow example with some dummy data demonstrating the problem? I tried to recreate it based on your description, and couldn’t reproduce the issue. Here the Column Aggregator is producing an expected warning, not a failure:


The snapshot you show is the problem I have.
The column aggregator node cannot proceed as there is now no aggregation column. I would consider it an error rather than a warning as the node cannot proceed.
I would have hoped the catch node could take the 2nd port and proceed.


In that case, as a workaround you could use a Column Expressions node to to do the aggregation instead. If it doesn’t find the columns it’s looking for, it will throw an error, and the Try/Catch construct will behave as intended:

2022-08-12 17_13_43-KNIME Analytics Platform

Does that work for you?

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Thanks that works for me.



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