The number of messages sent to the consumer at the same time can be specified through the prefetch count value. The prefetch count value is used to get as much out of the consumers as possible.

If the prefetch count is too small, it could negatively affect the performance of RabbitMQ, since the platform is usually waiting for permission to send more messages. The following diagram shows an example of a long idle time. The example has the prefetch set to one, meaning that RabbitMQ will not send the next message until after the delivery, processing, and acknowledgment of the message is complete.

In the example, the processing time is only 5 ms, with a round-trip time of 125 ms (60 ms + 60 ms + 5 ms):

A large prefetch count makes RabbitMQ send many messages from one queue to one consumer. If all messages are sent to a single consumer, it may be overwhelmed and leave the other consumers...