rails

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

Traditional offset-based pagination becomes unreliable and slow for large datasets when records are frequently inserted or deleted—users can miss items or see duplicates across pages. Cursor-based pagination solves this by using an opaque token that e

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.

Proper indexing is the difference between millisecond and multi-second query response times. I add indexes to foreign keys automatically since Rails doesn't do this by default, and I create composite indexes for common query patterns that filter on mu

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.

Direct uploads are great because they keep file traffic away from your Rails dynos, but the default UX is opaque. I attach a Stimulus controller that listens for Active Storage’s direct-upload:* events and updates a progress bar. This keeps the markup