(node:87) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 unhandledRejection listeners added to [process]. Use emitter.setMaxListeners() to increase limit

[siddjain]

• Node.js Version:

node -v
v12.18.1

• OS:

uname -a
Linux b8d5107fc64e 3.10.0-1062.9.1.el7.x86_64 #1 SMP Mon Dec 2 08:31:54 EST 2019 x86_64 Linux

(using node:12-alpine Docker image)

I have following code:

process.on('unhandledRejection', (reason, promise) => {
  logger.error(`Unhandled Rejection at: ${promise} reason: ${reason}`);        
});

and it is triggering following warning:

(node:87) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 unhandledRejection listeners added to [process]. Use emitter.setMaxListeners() to increase limit

The code is not inside any for loop. I am executing it only once. It seems like a bug.

[Lancear]

add a log above the process.on('unhandledRejection', ...) and see how often it is logged. those 11 eventlisteners have to come from somewhere

[siddjain]

That's a good idea. Thanks. I tried it and see log message only once. 2020-10-28T17:36:59.813Z [Main] info: adding unhandledRejection handler (node:8) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 unhandledRejection listeners added to [process]. Use emitter.setMaxListeners() to increase limit

…

________________________________ From: Lance J. <notifications@github.com> Sent: Wednesday, October 28, 2020 2:41 AM To: nodejs/help <help@noreply.github.com> Cc: siddjain <siddjain@live.com>; Author <author@noreply.github.com> Subject: Re: [nodejs/help] (node:87) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 unhandledRejection listeners added to [process]. Use emitter.setMaxListeners() to increase limit (#3040) add a log above the process.on('unhandledRejection', ...) and see how often it is logged. those 11 eventlisteners have to come from somewhere — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<https://eur05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fnodejs%2Fhelp%2Fissues%2F3040%23issuecomment-717815661&data=04%7C01%7C%7Cc53be200647849245f0a08d87b25985b%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637394748678242731%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=ZvVGFPlNi3iPF0JHjF21nlMt6vnESYqUSAcnzQliFdE%3D&reserved=0>, or unsubscribe<https://eur05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fnotifications%2Funsubscribe-auth%2FAAFZEMJGIHMUSFNBV3YVAT3SM7RLFANCNFSM4TBSBO5Q&data=04%7C01%7C%7Cc53be200647849245f0a08d87b25985b%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637394748678252725%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=NF0wQcAXc0NJlKE6jkRrevoH4zRYUPvxSTHT1eEndVo%3D&reserved=0>.

[Lancear]

thats weird. is it possible you add that event handler somewhere else? maybe log the event-emitter with console.dir. i believe it shows the registered event handlers.

[preveen-stack]

@siddjain any updates on this issue? Did you get a chance to try with latest nodejs version

[github-actions]

It seems there has been no activity on this issue for a while, and it is being closed in 30 days. If you believe this issue should remain open, please leave a comment.
If you need further assistance or have questions, you can also search for similar issues on Stack Overflow.
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[github-actions]

It seems there has been no activity on this issue for a while, and it is being closed. If you believe this issue should remain open, please leave a comment.
If you need further assistance or have questions, you can also search for similar issues on Stack Overflow.
Make sure to look at the README file for the most updated links.