Script debugger stops at breakpoint, but its UI is hung

Michael255 · ‎03-26-2024

I have had an issue with one particular instance for a couple of weeks where the Script Debugger has started hanging. It correctly stops at breakpoints but clicking any button in the window does nothing. Ie. not play/pause/step into/step over.

Eventually the transaction times out and the debugger turns itself off.

I am successfully using the debugger in other instances, so I don't think it is a browser issue. I have tried disabling all browser plugins with no improvement.

Is anyone aware of something that might cause this behavior, from a setting to a known issue, etc.?

George13 · ‎03-27-2024

Here is the solution that we tried and it worked:

Try setting the system property "glide.ua.gcf.sample_priority.enabled" to false and see if the problem is still reproducible.
You may not find the system property. If so, create it and set it to false. The type of the system property should be 'true | false'

Please refer to the knowledge document below

https://hi.service-now.com/kb_view.do?sysparm_article=KB1637446
This system property is used to disable the optimistic priority feature in GCF data collection. According to ServiceNow support there is no impact on the instance if you the property to a false.
The only impact is that it can have a few sample drops in GCF which might be ok since its usage data so it is safe for you to add the workaround in other instances as well.

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George13 · ‎03-26-2024

Is your instance recently upgraded to Washington DC? We face the same issue only on Washington DC release

Michael255 · ‎03-26-2024

Hi @George13 ,

Our instances with the problem are still running Vancouver. Interesting that it is not unheard of.

j_dahm · ‎03-27-2024

Hi @Michael255 we have the same problem after a recent Release Upgrade to Vancouver Patch 7.

I can see that, for example the Step Over, is triggred but nothing happens till the Debugger times out after around 13 seconds and deactivates and the Script continues to run.

The Node-Log shows: WARNING *** GlideServlet:Transaction waited excessive time to run: 13876ms, semaphore wait: 0ms, session wait: 13876ms for /api/now/js/debugger/step-into.

Michael255 · ‎03-27-2024

Good observation. That matches the experience of trying to click a button in the debugger.