Line Reader & File Content Changed => not enabling execution of node

KNIME Analytics Platform
1

Hi, how do I get a Line Reader node to recognize a file content change so that it’s executed again?

I don’t understand why such a node is not always executed again.

Is there a way to set it into the consistently execute state, or avoid caching results?

2

Hi,
Reexecuting the node when a file changes would go against KNIME’s paradigm of workflow execution, where once a node is green, it provides static results and does not change again. If you want something like that, you’d need to wrap the node in a loop that checks the file’s last modification time periodically (you can slow it down with a Wait… node) and then runs the Line Reader if the file has changed.
Kind regards,
Alexander

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@robert_m_muench there is this component by @gab1one that might help:

I tried my hand at a workflow that would check if a file has changed and then do somthing:

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Thanks.

IMO, KNIME should have such an “Executing when something changed” node. It shouldn’t execute automatically, but when I press “Execute,” it should re-evaluate the file content and the downstream nodes.

5

Hi,
Manually, that is possible. You first need to reset the node and then you can re-execute it, and it will read the new file content.
Kind regards,
Alexander

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