Tiny explainers grouped by topic. Spend less time Googling, more time building.
A production-focused guide to right-sizing pools, setting timeouts that prevent stalls, and fixing Postgres/MySQL “too many clients/connections” errors with app and proxy patterns.
Change schemas safely with backward‑compatible steps, dual writes, background backfills, and rolling deploys. Postgres‑flavored, but patterns apply to MySQL and friends.
A practical mental model for indexes, with copy‑paste patterns for B‑tree, composite order, covering, partial, and expression indexes—plus when **not** to index.