Performance terms
Every millisecond matters — here is how to win them back
Slow software costs money, loses users, and erodes trust. Performance engineering covers profiling, caching strategies, database query optimisation, network latency, memory management, and the architectural patterns that keep systems fast under real-world load. Most performance problems are invisible until they are not — these terms help you find and fix them before your users do.
Core Web Vitals
Google's three field-measured performance metrics — LCP (loading), INP (interactivity), CLS (visual stability) — used as direct search ranking signals since 2021.
1mo ago
performance intermediate
Cumulative Layout Shift (CLS)
A Core Web Vital that measures unexpected visual movement of page elements during load — caused by images without dimensions, late-injected content, and font swaps. Target: under 0.1.
1mo ago
performance intermediate
Caching Strategies PHP 7.0+
Patterns for when and how to store and invalidate cached data — cache-aside, write-through, write-behind, and read-through each make different trade-offs between consistency, complexity, and performance.
2mo ago
performance intermediate
Cache Warming Strategies PHP 5.0+
Pre-populating a cache before traffic arrives — preventing the cold-start thundering herd where every request misses a cold cache simultaneously after a deploy.
2mo ago
performance intermediate
Cache Stampede / Thundering Herd PHP 5.0+ When a cached item expires, multiple simultaneous requests all miss the cache and hit the database concurrently, overwhelming it.
2mo ago
performance advanced
Caching Strategies (APCu, Redis, Memcached) PHP 5.0+ Storing computed results or fetched data so future requests can be served without repeating expensive operations.
2mo ago
performance intermediate
CDN (Content Delivery Network) A geographically distributed network of servers that caches and delivers static assets from locations close to end users.
2mo ago
performance beginner
CDN Edge Caching PHP 5.0+ Content Delivery Networks cache responses at edge nodes close to users — reducing latency and origin load, controlled via Cache-Control headers.
2mo ago
performance intermediate
Connection Pooling PHP 5.0+ Reusing a pool of pre-established database connections rather than opening and closing a new connection on every request.
2mo ago
performance intermediate
Connection Pooling — pgBouncer & ProxySQL PHP 5.0+
External connection poolers sit between PHP-FPM and your database — multiplexing hundreds of PHP connections onto a small pool of real DB connections.
2mo ago
performance advanced
Covering Index An index that contains all columns referenced by a query, allowing the database to answer it entirely from the index without touching the table.
2mo ago
performance intermediate