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Article ID: 1074 - Last Modified:

When processing large data sets, KNIME seems to be running out of memory. What can I do?

By default KNIME uses a maximum of 1024 MB of heap space for the Java Virtual Machine (JVM). When processing very large data sets this amount might not be sufficient, and you may see messages similar to the following:

java.lang.OutOfMemoryError: Java heap space
FATAL node-name Fatal error
FATAL node-name Java heap space

If you are using the Schrödinger installation to start KNIME, you can change the memory limit by with the -maxHeap memory option, for example:

$SCHRODINGER/knime -maxHeap 2048m

On Windows, you can edit the KNIME shortcut on the desktop to add this option.

To change the default memory, you can change the settings in the file
knime.ini, which is in your installation in the directory knime-vversion/bin/arch/knime/. The file should contain the following settings:


In order to increase the amount of heap memory you should change the -Xmx setting. For example, to allocate 2048 MB of heap space to the JVM you should change -Xmx1024m to -Xmx2048m.

Keywords: crash, error

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