MaxListenersExceededWarning with worker_threads in node.js

[Michsior14]

Currently there is no way to set max listeners (10 by default) for worker_thread, thus if you have high load across more than 10 threads the warning will popup.

I am interested in fixing this upstream either by setting the listeners value to higher value (e.g. 100) by default or providing the new option for WorkerHandler. What would be your preference?

[josdejong]

Thanks. Some questions/thoughts:

1. Is there a downside to just setting a higher value like 100?
2. Is this something users will want to fiddle with?
3. Can we automatically set max listeners according to the configured maxWorkers option?

[Michsior14]

1. Could be harder to detect potential memory leak, although I saw similar fixes for worker implementations.
2. Possibly yes, in some cases it can narrow down the place where leak could occur.
3. Maybe, I would need to check a bit more the implementation to make sure it's feasible (e.g. are the listeners cleared/shared across the worker calls).

[josdejong]

Ok so it makes sense to have the setting configurable, like for debugging memory leaks. It would be nice if we can reuse maxWorkers for this I think, please let me know if you think that will work.

[Michsior14]

Uhhh, it turned out that it's not workerpool fault and everything works as expected here (only one listener for parent and one for child thread) . The issue was with sentry initialization during job execution. Sorry!

[josdejong]

👍