From Ruby to Elixir

Be Parallel, Be Cautious

With great power comes great responsibility. Elixir is a powerhouse when it comes to running parallel processes. You can literally spin up thousands of concurrent requests that are active at the same time. But this can cause problems.

Programs don’t exist in a vacuum. They interact with other programs like databases or external APIs. A program can only handle so many parallel requests before it becomes overwhelmed. You could easily exhaust a database connection pool or downstream API service by sending too many simultaneous requests.

It’s best to always have control over the amount of parallelism in your system. Libraries that you’ll see later in this book, like Ecto and Oban, all include a limited number of parallel ...