Heap memory contains 6.3 million of string objects like this: amq.ctag-QyDNazNXZdatTGscA8QWrw

[gabrieltarpian25]

Describe the bug

Hello, everyone. I have multiple microservices that communicates each other with RabbitMQ. I have discovered that my application is having high memory usage that keeps growing. I have analyzed its dump and I found that, on the heap memory, I have 437 MB used by around 6.3 million of string objects like this: amq.ctag-QyDNazNXZdatTGscA8QWrw

This is the consumer tag. I am not storing it on the heap, it's just within the local scope in a string variable, so I am pretty sure the Garbage Collector will dispose it. I am creating a consumer for each RPC request, like this:

var consumer = new AsyncEventingBasicConsumer(channelFromMessage);
consumer.ReceivedAsync += Consumer_ReceivedAsync;

And cancel it like this:

await rpcPublishChannel.BasicCancelAsync(consumerTag, cancellationToken: cts.Token);
consumer.ReceivedAsync -= null;

From my research, it seems the consumer was disposed but not its handler and that's why its tag stays in the memory. Could you please confirm that is the case? Also, should I replace

consumer.ReceivedAsync -= null;

with

consumer.ReceivedAsync -= Consumer_ReceivedAsync;

Thank you!

[gomoripeti]

This repository is about the server side, so RabbitMQ as a broker.
I think you have an issue with an AMQP client but you did not specify which client or which programming language you use.
Please submit this (probably as a discussion) in the repo of the AMQP client that you use.

[lukebakken]

@gabrieltarpian25 - I've moved this issue to the correct repository.

You are missing basic information in your issue report:

• Version of RabbitMQ and Erlang being used.
• The version of RabbitMQ.Client you're using.
• Complete code to reproduce the issue. I should be able to clone, build, and run it.

Once you provide the above, I can assist you.

Other notes:

consumer.ReceivedAsync -= Consumer_ReceivedAsync;

Yes, that is the correct way to remove an event handler in C#.

From my research, it seems the consumer was disposed but not its handler and that's why its tag stays in the memory. Could you please confirm that is the case?

How am I supposed to confirm this without seeing how you use this library? After a quick review I can't see where this library would hold on to a consumer tag for a long period of time in ConsumerDispatcherBase.