DB writer stops in the Loop

Hey Guys short Question. I have that Process which write my Data back into different DB Tables.

Everything’s going well, too. But the DB Writer stops with that Error after the first loop.

"WARN DB Writer 0:57 Included column list contains invalid column(s)!"

Everything is well configured and it insert the Data correct if i execute the db writer and the loop manually.

Is this a bug??

Who can help me please ?

Best regards

To be able to provide more advice we would need more information and context:

  • ideally you would be able to provide a working example that produces the error
  • alternatively you might clear your knime.log file and run the workflow again and provide us with the log
  • you could give us more context about the data you want to use (structure etc.)
  • you could give us screenshots of the DB writer configuration

One possibility is that there already is a data table from an earlier test, because by default I think the DB writer tries to append to an existing table (which makes sense in a loop). For starters I would recommend adding a node that deletes your target table if it is already there at the beginning of the loop.

1 Like

Hi there,

seems like a bug. Ticket has been opened for this.



I’ve just experienced the same error. Here is my workflow:

Here is console log:
DB_writter_stops_in_a_loop.log (38.6 KB)
Here is the workflow:
DB Writer - different table definitions in a loop.knwf (53.8 KB)
This error has made me really stuck. Would you mind providing me with an estimation when this is expected to work correctly?
Thanks a lot.

Hello jan_lender,
thanks for providing the great example workflow. We will fix this problem with version 4.1 which is planned to be released on 6.12.


Hello everyone,
last Friday we released KNIME Analytics Platform version 4.1 which now allows you to use all DB Manipulation nodes (Writer/Insert/Update/Merge/Delete) with changing input table specs e.g. when used in a loop. Thanks again for your help to find this issue. I will close this post :slight_smile: