Our Elasticsearch cluster was costing more to babysit than it was saving us in query time. Here's what changed when we moved to a purpose-built Rust index, and the three assumptions that turned out to be wrong.
Every new tool promises to save you time. Most of them cost it instead. A short argument for choosing the stack you can debug at 3am over the one that looks good in a blog post.
Not another checklist. This is the actual six-week plan I followed, including the two mock interviews that made me rewrite my approach to estimating capacity from scratch.
Most explanations start with the ring and skip the problem it solves. We'll build one up from a naive modulo hash, watch it fall apart under a single node failure, and fix it step by step.
Most style guides are aspirational. This one only contains rules our linter enforces, because the rest just becomes a document nobody reads during review.
I shipped my first real PR to a project with 40,000 stars and got it merged in a day. I also had three PRs sit unreviewed for months. Both taught me something about how maintainers actually work.
The heap graph looked fine for six hours, then climbed for six minutes and paged the whole team. A walkthrough of the leak, the wrong turns we took, and the one flag that gave it away.
Not because anyone will read them closely, but because writing one forces you to notice the three decisions you were about to make by accident.