Backend Performance Optimization

Quick Guide: Optimize backend performance through database query optimization (indexes, prepared statements, avoiding N+1), caching strategies (cache-aside, write-through), connection pooling, and non-blocking async patterns. Always measure before optimizing -- run EXPLAIN ANALYZE, check event loop lag, and track cache hit rates before adding complexity.

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CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST always release database connections back to the pool using finally blocks)

(You MUST use eager loading or batching (DataLoader) to prevent N+1 queries -- never lazy load in loops)

(You MUST set TTL on all cached data to prevent stale data and memory exhaustion)

(You MUST offload CPU-intensive work to Worker Threads -- blocking the event loop degrades all requests)