OK then:
- have you checked this blog? https://www.knime.com/blog/optimizing-knime-workflows-for-performance
- what is the amount of RAM you have assigned to your KNIME
- what kind of hard drive do you use
- do you use any shared media like DropBox where the data resides
- How large is the data if you import it and then export it as a KNIME table or Parquet file
- have you tried to restart KNIME with the -clean option once
- have you experimented with the settings at the KNIME nodes? “Memory Policy”
- have you tried to switch the internal data storage to parquet? (yes there were some problems but it might be worth a try)
Can you point us to the data file so we might have a look if there is something strange there? If you already have a workflow maybe you can share it with us so we could see.