Memory Leak - internal/process/warning.js

[renanbastos93]

• Node.js Version: v9.8.0
• OS: bash ubuntu windows10

Hey guys,

I'm with problem of memory leak, but this is a problme of lib internal, somebody help-me with immediate.

Thanks, see ya.

[apapirovski]

You're adding a lot of error listeners to a single instance of event emitter (or something that inherits from it). Have a look through your code and/or post the full stack trace.

[renanbastos93]

This is the message I get
internal/process/warning.js:18 (node:1609) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 error listeners added. Use emitter.setMaxListeners() to increase limit

I'm using too try catch with expressjs my route this used async await.

 try{
        
        let key = `getCustomerById-${request.params.id}`;
        let keyExist = await repositoryRedis.getKeyExist(key);
        
        if(keyExist == false) {
            let result = await deviceService.getAll(request.params.id);
            response.status(200).json(result).end();
            repositoryRedis.save(key, JSON.stringify(result), config.get('redis.expire.deviceList'));
        }else{
            let result = await repositoryRedis.getValue(key);
            let deviceList = JSON.parse(result);
            response.status(200).json(deviceList).end();
        }

    }catch(error){
        response.status(500).json({message: "Error internal 500 - Device List All by Customer Id"}).end();
    }

Did I make myself clear?

[apapirovski]

There's no error listeners in that code so all I can assume is that something else is binding them. You're looking for .on('error, ...) or .addListener('error', ...). Could be whatever that redis code is or could be something about how this block is being executed.

You could try putting some breakpoints and seeing what exactly is binding this many event listeners.

[renanbastos93]

Hey dude,

I did comment all listeners, I had this code in all the methods of repository redis.

client.on("error", function (error) {
       throw error;
});

Now, no errors.

thanks a lot.

see ya.

[advanceddeveloper]

@renanbastos93

Good to hear that you've solved the problem. One thing that I think is worth mentioning is that, as I can see, all your event listener functions are actually closures. Notice that when you call onOpen, onClose, onAcquire and probably few more function that you have there, they will return an unique closure. If you call them again with same fd argument, they will return different closure. In future, if you would like to remove such listener, you'll need to save the reference to the initial closure.

[apapirovski]

@advanceddeveloper That's the Node.js source code.

https://github.com/nodejs/node/blob/master/lib/internal/process/warning.js

[renanbastos93]

Oh @advanceddeveloper ,

I understood, but as I save this reference of closure? When? Where?

see ya.

[advanceddeveloper]

@apapirovski

Oops... my bad :/
But anyway, I think the advice I was talking about is useful, in general.