Requests through API Gateway → Lambda → DynamoDB are slow, but no single component looks wrong in logs. Which tool shows WHERE latency accumulates across the request path?
A.CloudWatch Logs for each component
Per-service logs don't stitch timing across a request path.
B.AWS X-Ray service map and trace subsegments
Correct. Subsegments attribute latency to each hop.
C.VPC Flow Logs
Flow logs show packet accept/reject, not application latency.
D.AWS Config timeline
Config tracks resource configuration, not request timing.
Why this answer
X-Ray traces requests end-to-end — the service map shows nodes and edges, and subsegments reveal per-hop latency (e.g., DynamoDB SDK calls vs Lambda init). Exactly the tool for 'where does the time go' questions.
Correct answer: B · Last reviewed 2026-10-26
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