Monitor Loop Progression in the Knime Console - Example Workflow

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Hi KNIME community!

I wanted to share a helpful method, including an example workflow, for tracking loop progress in KNIME, which is especially useful in long-running workflows or when using Parallel Chunk Loop Nodes.

This approach uses a Java Snippet node to create a console-based progress bar that updates on each loop iteration. With this progress indicator, you can:

  • Monitor loop progress in real-time.
  • Debug potential bottlenecks.
  • Gain insight into resource distribution in parallel executions.

Here’s a quick example of the Java code for the progress bar:

int progressPercentage = (int) (((v_currentIteration + 1) / (double) v_maxIterations) * 100);
StringBuilder progressBar = new StringBuilder("[");
int totalBars = 20; // Number of segments in the progress bar
int completedBars = (progressPercentage * totalBars) / 100;

// Add completed segments
for (int i = 0; i < completedBars; i++) {
    progressBar.append("\u2588");
}

// Add remaining segments
for (int i = completedBars; i < totalBars; i++) {
    progressBar.append("\u2591");
}
progressBar.append("]");

// Log the warning with the progress
logWarn(
	"\n\n\n\n\n\n/****************************************\n/****************************************\n/****************************************" +
	"\n/************ New Iteration *************" +
	"\n/****************************************\n" +
	"Iteration: " + v_currentIteration + " // Total Iterations: " + v_maxIterations + "\n" +
	"Progress: " + progressPercentage + "% " + progressBar.toString() + "\n\n\n"
);

knime-loop-progress-monitoring-console
knime-loop-progress-monitoring-console1530×367 34.5 KB

If you’re running loops in parallel, this setup can also help monitor each chunk’s progress separately, making it easier to manage and debug complex workflows.

Here is the example workflow:

Feel free to reach out if you have questions or improvements to share! :blush:

Read my full blog post on my homepage:

https://atmedia-marketing.com/en/knime/knime-loop-debugging-and-progress-tracking/

Best
Mike

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