Warn: WARN List Files/Folders Column Data Cache is disabled. Consider enabling it in the Columnar Table Backend preferences

Dear KNIMER´s,

I always get this error message even though I have the column data cache enabled:

I´m using KNIME 4.7.0 and KNIME Columnar Table Backend 4.7.0.v202211291058

Any pointers?

Kind regards,


@goodvirus can you tell us your operating system and maybe a log in debug mode. I am collecting hints about problems with parquet and arrow data formats.

Also: can you try and uninstall and reinstall the extension.

Hi @mlauber71,

thanks for the fast reply. I´m running Windows 10 Enterprise with 32 Gb ram an i7 processor.
Uninstalling the extension is not possible, I think because its part of the default KNIME installation now:
“KNIME Columnar Table Backend” cannot be fully uninstalled because other installed software requires it. The parts that are not required will be uninstalled.
But I found that there is an update, so I updated to " KNIME Columnar Table Backend 4.7.1.v202301311311, but still no difference.

An there seems to be no information in the log about that problem:
log.txt (42.7 KB)

Kind regards,


Hi @goodvirus,

the error is interesting. We have seen something similar on Mac because there the amount of “free” RAM is usually close to zero (because OSX caches a lot of things while the memory is not directly required by other processes).

When you select “Use default values” we do try to estimate a good size of the cache based on the amount of free RAM. If the amount of free RAM is zero, then this error can be shown - because if the estimated cache size is zero we disable the cache.

Could it be that your RAM is completely full? Does this error also show up if you restart the computer and start KNIME before starting a lot of other programs?

How much RAM did you allocate to the JVM for KNIME (configured the -Xmx setting in the knime.ini), is there anything left for the system? E.g. if you allocate 32GB to the JVM while having 32GB of RAM, the estimated cache size will also be zero.

If any of these are the reasons for this error message to show up, we should definitely improve the message to give better hints :slight_smile:

Hope that helps,


Ah and @mlauber71 good suggestion about re-installing the extension. However, as @goodvirus correctly assessed, the columnar backend is part of the default install and is used also by other plugins (e.g. the Python Integration) and thus it’s hard to uninstall.


@carstenhaubold not sue if this is related but I still fear there are some systematic problems with the implementation of these data storage formats at least on Apple silicon machines (AP-19918, AP-19894). Mine is currently unusable and I use the intel one (missing out on the 20%+ speed improvement) - but there are more reports about components that should be installed which are not or might not show up or are unable to uninstall. Might not be related but I was noticing a pattern.

Also “RDKit” and similar messages seem to pop up a lot. Tried to uninstall and reinstall related packages but to no avail.


No, these things are not related. But the naming of the features is misleading, unfortunately:

KNIME’s Apache Parquet or ORC “Column Storage” formats are features of the “default” table backend, whereas the “Columnar Backend” is a complete rewrite of KNIME’s table backend (which uses Apache Arrow in turn). The problems you are seeing @mlauber71 are that the Apache Parquet and ORC Column Storage Features are not working properly with Apple silicon, while our “Columnar Backend” is definitely working on Apple silicon - otherwise the new Python Integration wouldn’t work on Apple silicon KNIME builds.

@goodvirus’ issue was on a Windows machine when using the “Columnar Backend”, so the Apple silicon incompatibilities shouldn’t be a problem here.

Hope that resolves the confusion a little.

The RDKit errors however are definitely there in the logs, did you try to re-install / update that extension @goodvirus? We have updated the RDKit extension for KNIME 4.7 quite substantially.


Yes they do :slight_smile: - I was just wondering if there might be more to it components not being able to be installed, and also not showing up on the startup graphic (like they would). Sticking to Intel/Rosetta for the moment on Mac. Windows running just fine.

Hi @carstenhaubold,

i think this was the problem. I had -Xmx29000m as a setting, because I wanted KNIME to use most of my ram. I reduced it and the error is not happening anymore. The question now is, how do I give KNIME as much memory as possible, but also have the column backend?


I don’t have RDKit installed as far a I know. This are my installed extensions:

Geospatial Analytics Extension for KNIME sdl.harvard.features.geospatial.feature.group SDL, Harvard, Cambridge US
KNIME Amazon Cloud Connectors 4.7.0.v202301311059 org.knime.features.cloud.aws.feature.group KNIME AG, Zurich, Switzerland
KNIME Amazon Machine Learning Integration 4.7.0.v202211082351 org.knime.features.cloud.aws.mlservices.feature.group KNIME AG, Zurich, Switzerland
KNIME Analytics Platform 4.7.1.v202301311353 org.knime.desktop.product null
KNIME Azure Cloud Connectors 4.7.0.v202211161540 org.knime.features.ext.azure.feature.group KNIME AG, Zurich, Switzerland
KNIME Chromium Embeded Framework (CEF) Browser 4.7.1.v202301311311 org.knime.features.browser.cef.feature.group KNIME AG, Zurich, Switzerland
KNIME Columnar Table Backend 4.7.1.v202301311311 org.knime.features.core.columnar.feature.group KNIME AG, Zurich, Switzerland
KNIME Connectors for Common Databases 4.7.0.v202211120527 org.knime.features.dbdrivers.feature.group KNIME AG, Zurich, Switzerland
KNIME Data Generation 4.7.0.v202211082353 org.knime.features.datageneration.feature.group KNIME AG, Zurich, Switzerland
KNIME Database 4.7.0.v202211231356 org.knime.features.database.feature.group KNIME AG, Zurich, Switzerland
KNIME Ensemble Learning Wrappers 4.7.0.v202206271101 org.knime.features.ensembles.feature.group KNIME AG, Zurich, Switzerland
KNIME Excel Support 4.7.0.v202211171209 org.knime.features.ext.poi.feature.group KNIME AG, Zurich, Switzerland
KNIME Expressions 4.7.0.v202211082355 org.knime.features.expressions.feature.group KNIME AG, Zurich, Switzerland
KNIME External Tool Support 4.7.0.v202211151738 org.knime.features.ext.exttool.feature.group KNIME AG, Zurich, Switzerland
KNIME External Tool Support (Labs) 4.7.0.v202206271101 org.knime.features.exttool.feature.group KNIME AG, Zurich, Switzerland
KNIME H2O Machine Learning Integration 4.7.0.v202211220919 org.knime.features.ext.h2o.feature.group KNIME AG, Zurich, Switzerland
KNIME Hub Integration 4.15.0.v202211281224 com.knime.features.workbench.hubview.feature.group KNIME AG, Zurich, Switzerland
KNIME Image Processing org.knime.knip.feature.feature.group University of Konstanz / KNIME
KNIME Interactive R Statistics Integration 4.7.0.v202211090002 org.knime.features.r.feature.group KNIME AG, Zurich, Switzerland
KNIME JavaScript Views 4.7.0.v202211091556 org.knime.features.js.views.feature.group KNIME AG, Zurich, Switzerland
KNIME JavaScript Views (Labs) 4.7.0.v202207221134 org.knime.features.js.views.labs.feature.group KNIME AG, Zurich, Switzerland
KNIME Javasnippet 4.7.0.v202211082357 org.knime.features.javasnippet.feature.group KNIME AG, Zurich, Switzerland
KNIME JSON-Processing 4.7.0.v202212030000 org.knime.features.json.feature.group KNIME AG, Zurich, Switzerland
KNIME Machine Learning Interpretability Extension 4.7.0.v202211082358 org.knime.features.mli.feature.group KNIME AG, Zurich, Switzerland
KNIME Math Expression (JEP) 4.7.0.v202208041429 org.knime.features.ext.jep.feature.group KNIME AG, Zurich, Switzerland
KNIME Network Mining 4.7.0.v202211082359 org.knime.features.network.feature.group KNIME AG, Zurich, Switzerland
KNIME Network Mining distance matrix support 4.7.0.v202206271101 org.knime.features.network.distmatrix.feature.group KNIME AG, Zurich, Switzerland
KNIME NGS tools 0.2.300.qualifier org.pasteur.pf2.ngs.feature.feature.group Plate-forme 2 - Transcriptome et Epigenome, Institut Pasteur, Paris.
KNIME Office 365 Connectors 4.7.1.v202301311356 org.knime.features.ext.office365.filehandling.feature.group KNIME AG, Zurich, Switzerland
KNIME Parallel Chunk Loop Nodes 4.7.0.v202211090007 org.knime.features.virtual.feature.group KNIME AG, Zurich, Switzerland
KNIME Personal Productivity Tools 4.7.1.v202301312109 org.knime.features.personalproductivity.feature.group KNIME AG, Zurich, Switzerland
KNIME Plotly 4.7.0.v202211090000 org.knime.features.js.plotly.feature.group KNIME AG, Zurich, Switzerland
KNIME Public Server Access 4.7.1.v202302021000 com.knime.features.enterprise.client.exampleserver.feature.group KNIME AG, Zurich, Switzerland
KNIME Python 2 Integration (legacy) 4.7.1.v202301311311 org.knime.features.python2.feature.group KNIME AG, Zurich, Switzerland
KNIME Python Extension Development (Labs) 4.7.1.v202301311311 org.knime.features.python3.nodes.feature.group KNIME AG, Zurich, Switzerland
KNIME Python Scripting extension 4.3.0.v202301240921 de.mpicbg.tds.knime.scripting.python.feature.feature.group Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
KNIME Quick Forms 4.7.1.v202301311311 org.knime.features.js.quickforms.feature.group KNIME AG, Zurich, Switzerland
KNIME REST Client Extension 4.7.0.v202210211111 org.knime.features.rest.feature.group KNIME AG, Zurich, Switzerland
KNIME ServerSpace 4.16.1.v202301311407 com.knime.features.explorer.serverspace.feature.group KNIME AG, Zurich, Switzerland
KNIME Shapefile Support 1.6.0.v202212100552 de.bund.bfr.knime.esri.feature.feature.group Christian Thöns
KNIME Statistics Nodes 4.7.0.v202206271529 org.knime.features.stats.feature.group KNIME AG, Zurich, Switzerland
KNIME Statistics Nodes (Labs) 4.7.0.v202211090004 org.knime.features.stats2.feature.group KNIME AG, Zurich, Switzerland
KNIME Textprocessing 4.7.0.v202211181006 org.knime.features.ext.textprocessing.feature.group KNIME AG, Zurich, Switzerland
KNIME Textprocessing German Language Pack 4.7.0.v202206271102 org.knime.features.ext.textprocessing.language.german.feature.group KNIME Gmbh, Konstanz, Germany
KNIME Timeseries nodes 4.7.0.v202209020834 org.knime.features.timeseries.feature.group KNIME AG, Zurich, Switzerland
KNIME XGBoost Integration 4.7.0.v202211082337 org.knime.features.xgboost.feature.group KNIME AG, Zurich, Switzerland
KNIME XML-Processing 4.7.0.v202211082337 org.knime.features.xml.feature.group KNIME AG, Zurich, Switzerland
Palladian for KNIME ws.palladian.nodes.feature.feature.group palladian.ws
Redfield BERT Nodes se.redfield.bert.feature.feature.group Redfield AB
Redfield NLP Nodes se.redfield.textprocessing.feature.feature.group Redfield AB
Vernalis KNIME Nodes 1.36.1.v202212051049 com.vernalis.knime.feature.feature.group Vernalis Research Ltd, Cambridge, UK

I think the errors show up during loading of the Vernalis extension, it could be that it depends on RDKit (the log says An error occurred while automatically activating bundle com.vernalis.knime.chem.mmp)

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Hi @carstenhaubold ,

I just installed RDKit and the error is gone. But interesting, that KNIME didn’t automatically installed all the decencies when I installed vernalis.

Kind regards,


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