optimization

ActiveRecord provides powerful query interface, but naive usage causes N+1 queries. includes eager loads associations in 2-3 queries. joins performs SQL JOINs for filtering. preload always uses separate queries; eager_load forces LEFT OUTER JOIN. I us

Android performance optimization ensures smooth 60fps UI and efficient resource usage. I use Android Profiler to monitor CPU, memory, network, and energy. Layout Inspector identifies overdraw and deep view hierarchies. Systrace captures system-level t

Cow<'a, T> (clone on write) holds either a borrowed or owned value. It borrows when possible and clones only when mutation is needed. I use Cow<str> for APIs that might need to modify a string: if no changes are needed, it stays borrowed;

N+1 queries are the most common Rails performance problem—loading associations in loops causes exponential database queries. The Bullet gem detects N+1s in development and suggests fixes. It monitors queries and alerts when you should use includes, pr

rack-mini-profiler reveals performance bottlenecks in Rails apps. It displays database queries, rendering time, memory allocation on every page. I use Flamegraphs to visualize where time is spent. Memory profiling identifies allocation hotspots. Query

ProGuard and R8 shrink, obfuscate, and optimize Android apps for release builds. R8 is the default tool, combining shrinking and desugaring. I configure rules in proguard-rules.pro—keeping classes used by reflection, serialization, or native code. -ke

React.memo prevents unnecessary re-renders of components when props haven't changed. I wrap components in memo when they're expensive to render or receive the same props frequently. The component only re-renders if props differ via shallow comparison.