Day 64

Today, I:

• restarted working for Spacely as a freelancer — had a nice long rest, but it's time to go back
• relearned about the GVL (Global VM Lock) — MRI only runs one thread of Ruby code at a time, but releases the GVL during blocking I/O (DB, HTTP, disk), so in a high-I/O Rails app many threads can still wait on I/O in parallel; CPU-bound work stays serialized unless you scale with processes
• used rack-mini-profiler on a project — really useful for request timing, SQL, and jbuilder render breakdowns in local Rails; used to reach for Datadog for this kind of data, but this is way more practical in development
• realized I've relied too much on Ruby and Ruby on Rails "magic" — parts like ActiveSupport::Concern were mystery; at work it was more about shipping features than the language/framework intricacies, so I decided to spend some time per day on learning more about the language and framework by chatting with LLM, reading articles, and reading the source code.