Rails adds support for Fiber-safe ActiveRecord ConnectionPools | Saeloun Blog

One of the major focuses for Ruby 3 was parallelism and concurrency. A trailblazer in this space is the use of Ruby Fibers. Fibers are a concurrency mechanism that allows us to pause, loop, and resume execution while consuming far fewer context switches. It consumes less memory than threads while giving the developer control over code segment execution.Fibers are the best solution for scalable non-blocking clients and servers. However, it has taken Rails a while to make use of it.