Strange warning when running new 3.6 DB nodes (preview)

I get this warning in the console a lot (a few times per 1-2 hour session) when working with the new DB nodes, don’t remember seeing it before.

WARN KNIMEApplication$3 Potential deadlock in SWT Display thread detected. Full thread dump will follow as debug output.

Shall I worry?

For information what this message is about have a look at this topic: What means the message "potential deadlock"/"full thread dump will follow as debug output"

Is it somehow possible for you to provide an example for us that reproduces the issue? And the knime.log would be helpful as well.

Thank you, Marten.
It would not be possible to provide a workflow, as I only saw it when working with large datasets in on-premises Teradata instance while using the new DB nodes.
But I can send a log next time it happens. Are there any special instructions on how to submit a log?

You can save the log file from within KNIME by going to View->Open KNIME log and then go to File->Save as and then send the log file via personal message to me.

Did this also happened with the older DB nodes? What db nodes are you using or which nodes are in execution state when the log message is created? Do you experience that KNIME is not responding to any UI input when you work with the new db nodes?

Thanks a lot for your valuable feedback

Hi Tobias,

I have the log redy - how do I send a personal message?

I never noticed this warning when working with the old nodes. It usually appears when configuring DB nodes, not sure if there is a pattern. I have a feeling that it has something to do with KNIME sending a query to DBMS in the background and waiting for response. Sometimes I have an open session in a different application, with a query running in the same dabase, which makes DB nodes extra slow.

The UI freezes all the time when configuring the new DB nodes, usually for a few seconds but sometimes for a lot longer, and (Not responding) appears in the window titles in those cases.

To send him a personal message, just navigate to his profile page (easiest by clicking on his user name) and you will find a “Message” button in the top right corner.

Opened the profile page - can’t see any messaging buttons anywhere on the page. Maybe that function is only enabled for certain users or levels, etc.?

Hi Dimitri,

does this happen when you close the node dialog? The new framework retrieves the metadata (e.g. column names and types) of the result object whenever the node input changes or the node dialog is closed. This allows you to configure subsequent nodes without the need to execute the current node. However this might introduce this problematic behavior if the db does not respond fast enough.

In the old database framework this was disabled by default (see screenshot below)

Can you please check if this option was enabled or disabled in your old flows. If this causes the GUI freezes we need to add this option to the new framework as well in order to fetch the metadata only during node execution.

Thanks a lot for your help

The issue happers without any detectable pattern, I have a feeling it occurs when I execute complex workflows with a lot of new DB nodes.

The old Database connection nodes that I used all have the “Retrieve metadata on configure” option disabled, I didn’t even know what it did.

When I close a new DB node after configuring it, the UI freezes for quite a bit, which is mildly annoying.
On one hand I like the fact that downstream nodes are ready to configure without exectuing upstream ones, but sometimes I just want to get on with the design and don’t mind executing upstream if I have to, but get no UI freezing in return.
So I think this option would be good to have.

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.