PERFORMANCE PROFILING REPORT

BASELINE METRICS
• Endpoint: GET /api/user/:id/analytics
• Current latency: 2,847ms (p95)
• Requests per second: 12
• Memory usage: 280 MB (heap)
• Error rate: 0.3%

PROFILING RESULTS

CPU FLAMEGRAPH ANALYSIS
Hotspots identified:
1. Database query executor: 42% of time
   → SELECT * query fetching 150k+ rows unnecessarily
   → Missing index on user_id + date columns
2. JSON serialization: 28% of time
   → Stringifying entire user object (1000+ fields)
3. Authentication middleware: 18% of time
   → Token verification running on every field resolver
4. Other overhead: 12%

MEMORY PROFILING
• Heap snapshots show 45 MB leaking per 1000 requests
• Root cause: Cached query results never cleared
• Event emitter listeners stacking (900+ listeners on single event)

DATABASE QUERY ANALYSIS
• Slow query: 2.1 seconds average (SELECT * from users)
• Query plan shows full table scan (no index used)
• Missing index on user_id would reduce to 8ms
• N+1 problem: 156 queries per request (should be 4)

BUNDLE SIZE & LOAD TIME
• Initial bundle: 2.8 MB (unoptimized)
• Tree-shaking opportunities: 420 KB unused code
• Parse time: 340ms on cold start

BEFORE & AFTER OPTIMIZATION
Before: 2,847ms p95 latency | 280 MB heap | 12 RPS

Optimization plan:
1. Add database index on user_id + date (reduces query to 8ms)
2. Implement query result caching (60-second TTL)
3. Lazy-load user fields (fetch only needed 20 fields)
4. Remove duplicate token verification middleware
5. Enable tree-shaking in bundle (remove 420 KB unused code)

Expected After: 240ms p95 latency | 120 MB heap | 95 RPS
Improvement: 91% latency reduction, 57% memory reduction