If a hot key expires, you can stampede your DB. race_condition_ttl lets one process recompute while others serve stale content briefly. This is a reliability pattern masquerading as caching.

Celery Beat schedules periodic tasks like cron jobs. I define schedules in settings or use the Django database scheduler. Tasks run at specified intervals or cron expressions. I use @periodic_task decorator or configure in CELERY_BEAT_SCHEDULE. For dy

Indexes dramatically improve query performance. I add indexes via Meta.indexes or db_index=True on frequently-filtered fields. Compound indexes help queries filtering on multiple fields. For text search, I use GinIndex on PostgreSQL. I index foreign k

Large JSON payloads consume bandwidth and increase latency, especially for mobile clients on slow connections. Rack::Deflater middleware automatically compresses responses using gzip when clients send Accept-Encoding: gzip headers. This typically redu

HashMap<K, V> provides O(1) average-case lookups, inserts, and deletes. Keys must implement Hash + Eq. I use it for caches, indexing, and associative data. Common methods: .insert(k, v) adds/updates, .get(&k) returns Option<&V>, .r

Media queries adapt layouts to different screen sizes using @media rules with breakpoints. I use mobile-first approach starting with base mobile styles and progressively enhancing with min-width queries. Common breakpoints are 640px (sm), 768px (md),

When queries become too complex for scopes—involving multiple joins, subqueries, or raw SQL fragments—I extract them into dedicated query objects. Each query object is a plain Ruby class that encapsulates one specific query pattern and returns an Acti

Prepared statements are useful when the same query runs in hot loops, but they come with lifecycle responsibilities. I prepare once (usually at startup), store the *sql.Stmt, and always close it on shutdown. The important detail is still using QueryRo

I used a transactional outbox when I needed my database write and my event publish to succeed or fail together. In OutboxEvent model, I treated the outbox like a queue: a durable row per event, a dedupe_key for idempotency, and a ready scope that pull

Under real concurrency, even ‘simple’ write paths can hit serialization failures, especially with stricter isolation levels. Instead of pretending it won’t happen, I wrap the transaction in a small retry loop with jitter. I only retry on known transie

Stimulus adds JavaScript behavior to HTML without building SPAs. Controllers attach to DOM elements via data-controller. I use Stimulus for modals, dropdowns, form validation, autocomplete. Actions connect events to controller methods via data-action.

Effective Git workflows enable smooth team collaboration. Git Flow uses main, develop, feature/*, release/*, and hotfix/* branches. GitHub Flow simplifies to main plus short-lived feature branches with pull requests. Trunk-based development commits di