SWTException: Invalid thread access

[mwiegand]

Hi,

the issue about an “SWTException invalid thread access” is occasionally and without an apparent reason triggered. I once reported that in another workflow.

SWTException Invalid Thread Access for IF-Loop with "loose ends"

Hi, I happen to erratically and thus not reproducible encounter “SWTException Invalid Thread Access” when using any if loop (Knime and Community If-Nodes). Based on what I experience I suppose the “loose ends”, i.e. a Table Creator, is or was already executed before the if-node was evaluated. Hence, resulting in a partially executed loop. As follows to examples. I believe this is happening in larger quantities in the recent past as the setup had not changed but Knime got updated. In the past …

Though, this time it’s a totally different context and, intriguingly, the node address ‘3:1126:0:972’ does not match the failing component:

The failing component is actually the one after which failed:

Here is the thread dump. I am running the lates 5.3.1 version but the issue also appeared more often since 5.3.0. It is not reproducible

240813 SWTException threaddump-1723531488501.tdump.txt (97.8 KB)

The failing component predominantly contains Selenium nodes (fyi @qqilihq) but also some from Vernalis (fyi @Vernalis).

PS: Just a thought … there were some windows to inspect data results still open. In an attempt to better understand the context I leveraged ChatGPT which noted the following leading to my assumption.

The error message "SWTException: Invalid thread access" typically occurs when SWT UI elements are accessed from a thread other than the UI thread. In SWT, all UI updates must happen on the UI thread, and attempting to update the UI from a background thread will trigger this exception.

Best
MIke

[qqilihq]

@mwiegand

“SWTException invalid thread access”

I see these all the time (and not directly related to any specific node extension, which typically do not access SWT) and so far just considered them KNIME resp. Eclipse “Stand der Technik” to use German Engineerspeak.

Does it happen with any specific node or specific interaction? (i.e. execution, configuration, …?)

So, sorry - cannot provide any further comment here.

-Philipp

[mwiegand]

No worries, it erratically happens and is really difficult to pin down. Since it happened more often in the past I go all out on logging and have VisualVM running all the time in the background.