@Martin2024 maybe you can give this example a try. The XML is initially 500 MB and does work on my M1 machine with 15 GB assigned to KNIME 5.4 and Columnar Backend activated for the workflow.
The handling of Path for XML or JSON requires some trials and experimenting unless you are very familiar with the structures (in the case of JSON also some ungroup might be necessary cf. also the additional links).
