A city property-lookup API saturates its origin database during peak citizen traffic. Which design best protects the database while improving response times?
Select an answer to reveal the explanation.
Short Explanation
Caching is the librarian’s card catalog—citizens get common parcel answers from ElastiCache or CloudFront instead of waking the whole records vault every time. Killing replicas or ditching TLS doesn’t protect the origin; it just makes the vault lonelier or less safe.
Full Explanation
Caching frequent property-lookup responses with Amazon ElastiCache and/or Amazon CloudFront protects the city’s origin database during peak citizen traffic while cutting latency for repeat reads. Hot parcel answers can be served from memory or from the edge so the relational vault is not woken for every identical lookup. That read-heavy civic pattern—protect origin, improve response time—is exactly what caching is for.
Deleting read replicas and forcing every lookup through a single writer fails by concept because it removes read scale-out and concentrates load on the primary, worsening saturation instead of relieving it. Disabling TLS on the API so clients retrieve parcels “faster” fails because removing encryption does not meaningfully protect the database, violates security baselines, and is not a caching or capacity strategy. Storing all parcel PDFs only in instance store on one EC2 host fails because instance store is ephemeral, single-host, and does not replace a durable database or a proper cache tier for API responses.
Exam caveat: When the problem is origin database saturation on read-heavy lookups, reach for caching (ElastiCache, CloudFront, or both) and/or read replicas—not for removing replicas, disabling TLS, or parking data on instance store. Caching reduces repeated origin hits; it does not replace transactional writes.
Operational check: Measure cache hit ratio, origin QPS before and after, TTL and invalidation behavior for parcel data that can change, and failover if the cache cluster is unavailable. If every citizen lookup still hits the writer with no cache layer, the protection design is missing.