Consumer buffer size control

[MetalRex101]

Is your feature request related to a problem? Please describe.

Having: A queue with 1 million messages, that needs to be consumed.

Once consumer started, it will read all the available messages into a buffer, which will cause the following:

1. Rabbit MQ will load all the messages from a disk to a RAM;
2. It will drastically increase client application memory consumption.

Describe the solution you'd like

It would be nice to have a setting for consumer buffer size (per consumer?).
Once buffer size is reached, RMQ client will not read new messages from RabbitMQ.

Describe alternatives you've considered

Alternative is to set fixed-sized buffer. Everything is better, than unlimited one.

Additional context

No response

[Zerpet]

The consumer prefetch count is the feature you are looking for. This is exposed in Channel.Qos() function: https://pkg.go.dev/github.com/rabbitmq/amqp091-go#Channel.Qos

By default there is no limit. You can set a default limit at the server level using the advanced config and the setting described here: https://rabbitmq.com/consumer-prefetch.html#default-limit

[MetalRex101]

@Zerpet, First of all, thank you very much for such a fast reply.
I will try it right now!

[MetalRex101]

It solved my issue! Thank you!

[lukebakken]

@MetalRex101 thanks for using RabbitMQ.

In general, if a GitHub project has "Issues" and "Discussions", it's best to start a new discussion unless you are certain you have found a bug, or that the feature you request isn't already implemented.