Breakpoint node to end a loop when encounter empty data table

Hi there,

My data operated in a loop sometimes create empty table.
Now I want the workflow end the current loop if encounter empty data table.
So I simply connect the Row Filter (who create the empty table) to Breakpoint node, and set the Breakpoint active for empty table condition.

However, this operation can not be done. The node throws out the following error:
Execute failed: Breakpoint halted execution (table is empty)

How can I properly use the empty table breakpoint condition?

Thanks in advance.


The Breakpoint condition -well- ends the workflow.

You should try and use the empty table switch. The nodepit should have working examples:


Hi, @mlauber71

Thanks for your reply.

I have read the breakpoint node and empty table switch node on nodepit, and try to figure out this.
But I still confused the same error occur.
Currently my workflow is like this, is it make sense?

If the table have data, write out the CSV files.
If no data, want the workflow just goes to next loop.

Can the breakpoint node halt the current loop, and move the workflow operation to next loop?



As @mlauber71 said, the Breakpoint node stops the flow, it doesn’t close the loop or current iteration.

Just forget about the Breakpoint node for now and use the Empty Table Switch this way:

Between the Empty Table Switch and the End IF nodes, use nothing for the bottom flow and put the rest of your nodes (except the Loop End) at the top flow. Then connect the End IF to the Loop End.

This way when the Row Filter node produces an empty table, you skip the rest of the flow and reach the Loop End instantly.



Hi, @armingrudd

Thanks for your reply. That’s cool! Understood!

But I found my workflow doesn’t continue the loop when table has data.
Perhaps it is because my real workflow contains insufficient node.
My workflow is like this:

This screenshot taken when the row filter produces normal data table.
Something not normal at loop end…

Could you please give me further advice?
Many thanks!

First, remove the variable port connection between Copy/Move Files and the Loop End. It produces an error when the bottom port of the switch node is active. The variables are passed through the data flow, you don’t need to do that.

Connect the bottom port of the Empty Table Switch to the bottom port of the End IF node and it will work fine.



It worked :star_struck:!
Thanks again!

It seems I have to consider whether the variable port should be connected or not.
I have started to use KNIME for several months, and I always connect variable port to loop end node :joy:, … I often use CSV writer before Loop end and seems no problem in those cases, but I didn’t consider the node before the writer.

Will continue to create new workflow and learn more about KNIME. :laughing:


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