How many queues are used in the design pattern?

The design pattern does not have a fixed number of queues. The usage and number of queues depend on the specific implementation of the pattern, its purpose, and the context of application.

For example:

• Producer-Consumer Pattern: Usually, one queue is used for data exchange between producers and consumers.
• Message Broker Pattern: Multiple queues may be used to route messages across different topics or types.
• Task Queue Pattern: Most often, one queue is used to store tasks that will be executed by worker processes.

In Golang, queues are often implemented using channels:

// Creating a buffered channel (queue)
tasks := make(chan int, 10) // Queue with 10 elements

// Sending an element to the queue
tasks <- 5

// Receiving an element from the queue
task := <-tasks

Thus, the number of queues is determined by the requirements of the task, not by the pattern itself. The pattern only describes the general structure of the solution, while the implementation dictates specific artifacts such as queues.