AWS Certified Developer Associate (DVA-C02) > Domain 4: Troubleshooting and Optimization > Optimization > 4.3.8 Analyze Application Performance Issues

4.3.8 Analyze Application Performance Issues

Analyze Application Performance Issues

Common Performance Issues

Symptom	Likely Cause	Tool to Diagnose
High latency	Cold starts, slow dependencies	X-Ray, REPORT line
Throttling	Concurrency/capacity limits	CloudWatch Metrics
Timeouts	Slow downstream service	X-Ray Service Map
Memory errors	Under-provisioned	REPORT Max Memory Used
Inconsistent latency	Cold starts	Init Duration in logs

X-Ray for Performance Analysis

Client → API GW (5ms) → Lambda (250ms) → DynamoDB (10ms)
                                        → External API (500ms) ← bottleneck!

Service Map: Visual bottleneck identification
Trace timeline: Per-service latency breakdown
Annotations: Filter traces by business context

CloudWatch Contributor Insights

Top-N contributors to metrics
DynamoDB: Most accessed partition keys
API Gateway: Most called APIs
VPC Flow Logs: Top talkers

Performance Optimization Workflow

1. Identify: CloudWatch Metrics (errors, latency, throttles)
2. Diagnose: X-Ray traces, Logs Insights queries
3. Analyze: REPORT line, Service Map, Contributor Insights
4. Optimize: Right-size, cache, async, batch
5. Verify: Compare metrics before/after

Exam Tip: X-Ray Service Map = visual bottleneck finder. Contributor Insights = top-N analysis. REPORT line = Lambda-specific performance data. Always measure before and after optimization.