Phase 6: Evaluate & Optimize (Lambda Migration)

Goal

Analyze real metrics and decide on full migration strategy

Tasks

• Collect 2 weeks of metrics from Phase 5
• Analyze cold start latency (target: <3s acceptable)
• Analyze actual costs vs predictions ($0.03/month estimated)
• Verify DynamoDB consistency (no race conditions)
• Verify S3 retrieval performance
• Decision: proceed with full migration or optimize

Metrics to Track

• Lambda cold start latency (p50, p95, p99)
• Lambda warm invocation latency
• DynamoDB read/write latency
• S3 retrieval latency
• Cost breakdown (Lambda, DynamoDB, S3, API Gateway)
• Error rates

Decision Tree

• If cold starts >5s → Explore GraalVM native image
• If costs >2x estimate → Consider provisioned concurrency or stay hybrid
• If consistency issues → Fix before proceeding
• If all metrics acceptable → Proceed to Phase 7

Cost Impact

$0 (analysis only)

Timeline

2 weeks (monitoring period)

Risk

None (evaluation only)

Related to #112 (closed) Blocked by gitlab.com/go-3/go-3/-/issues/121 (Phase 5)