rails

Avoid loading whole records when you only need to know if something exists. exists? is good; for complex joins, a scoped select(1).limit(1) can be clearer and keeps the DB workload low.

Jobs should accept simple primitives (IDs, strings), not full objects. It avoids serialization surprises and makes jobs resilient across deploys. This also reduces job payload size.

When I need a modal (new/edit/show), I avoid client-side templating by using a dedicated turbo_frame_tag as the modal container (often id='modal'). Links target that frame, so the response only replaces the modal content. Closing the modal is just swa

I stopped doing row-by-row imports once they started hammering the DB. In Migration (unique index), I added a real uniqueness guarantee on provider + uid, because bulk writes only stay correct if the database can enforce constraints. Then, in Bulk ups

Turbo Drive caches pages aggressively, which is usually great. For volatile admin dashboards (counts, queues, toggles) you often want no-cache to avoid confusing “stale UI” bugs. turbo_cache_control makes the intent explicit.

If you sort by a non-unique column (score, created_at), pagination can “skip” or “duplicate” records. Always add a secondary unique key like id for deterministic ordering.

When you need to invalidate caches by changing timestamps, use touch_all to avoid per-record callbacks. It’s fast, explicit, and doesn’t run unintended side effects.

OFFSET gets slower as tables grow and becomes inconsistent under writes. Keyset pagination is stable and fast: paginate by (created_at, id) cursor. This is a common “senior Rails” upgrade for activity feeds.

Backfills often fail because we accidentally load full records and associations. Use select to fetch only needed columns and find_each to keep memory flat. This is basic, but it’s where outages come from.

Heavy work inside a transaction increases lock time and deadlock risk. Use after_save_commit to schedule slow tasks (thumb generation, external sync) once the write is durable.

ETags are a simple high-impact performance lever: they reduce bandwidth and controller CPU. Use stale? with a stable ETag component list and last_modified so intermediary caches and browsers can do conditional GET.

Even without extra gems, you can validate incoming JSON payloads with small “contracts” that coerce and validate keys. It’s a strong reliability upgrade for webhook and API ingestion.