> For the complete documentation index, see [llms.txt](https://allqueue.gitbook.io/allq/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://allqueue.gitbook.io/allq/features/fair-queuing.md).

# Fair Queuing

As any application evolves, it is eventually recognized that prioritization in a queue is not enough. Low level kernel developers learned this decades ago, but it's strangely missing from almost every job queuing platform available.

Conceptually, queuing always starts out the same way, when you can't perform an operation in real-time, you need to store those jobs to be done ASAP. So you put them in a queue. Then you realize that some operations are more important than others, so you add prioritization to help identify jobs that need to get done ***Now*** vs ***Later***. At some point, you get enough jobs that you realize that your queue is full of jobs that are equally important, but some clients are being starved because the other clients got their 1 million items in the queue before anyone else, and so now a client has to wait **a long time** before even getting 1 job. This is where fair queuing comes in.

Fair queuing is about adding some sense of scheduling to queues, so that one client does not dominate the queue, and all clients have a fair chance to get a job to work on. 

There are many different algorithms for providing this type of scheduling.  In an ideal world, you would just have N queues for N clients, and you would round robin between those N queues. This becomes unwieldy when you start having thousands of clients or queues. AllQ (behind the scenes) uses a form of stochastic fairness queuing which takes a user provided "shard" key, and builds a hash based on that shard key, and stores jobs in queues based on that hash. This provides a way for there to be a finite number of queues, and still provide a statistically fair queuing algorithm (for jobs of unknown length).

Most of the complexity is hidden from the client in AllQ, and the fair queuing can all happen behind the scenes (and with configurable options via ENV variables)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://allqueue.gitbook.io/allq/features/fair-queuing.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.