SAA-C03 Exam Dumps : AWS Certified Solutions Architect - Associate (SAA-C03)

The correct recommendation is to useAWS Schema Conversion Tool AWS SCTtogether withAWS DMSand run afull load plus CDCmigration so Oracle and Aurora PostgreSQL stay synchronized during the staged application cutover. AWS prescriptive guidance for Oracle-to-Aurora PostgreSQL migration explicitly uses AWS SCT and AWS DMS for this pattern. Because the source workload has a high number of reads and writes, amemory-optimized replication instanceis the stronger fit for heavy replication activity. DataSync is not the service used for relational database migration. Selecting only the largest tables would not satisfy the requirement to keep all application data synchronized across the whole migration window.

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The application experiences unpredictable traffic spikes, which exceed the provisioned read and write capacity of the DynamoDB table, resulting in throttling errors. This is a classic scenario where on-demand capacity mode is the most appropriate solution.

Option A is correct because DynamoDB on-demand capacity automatically scales to handle sudden increases in traffic without requiring capacity planning. This eliminates throttling during unpredictable spikes and removes the operational burden of managing RCUs and WCUs. On-demand mode is particularly well-suited for workloads with variable or spiky access patterns.

Option B is incorrect because DynamoDB does not support read replicas in the same way as relational databases. Option C reduces cost for predictable workloads but does not prevent throttling if capacity limits are exceeded. Option D increases read cost and does not address capacity constraints.

Therefore, A is the best solution to improve resilience, eliminate throttling errors, and ensure a smooth user experience during traffic surges.

The best answer isAPI Gateway + SQS + DLQ + Lambdabecause it combines API ingestion with durable queuing and asynchronous processing. AWS guidance for event-driven serverless architectures specifically recommends usingAmazon SQSto decouple components and durably persist messages when downstream processing is slower or bursty. AWS also documents thatdead-letter queueshelp isolate messages that fail processing, which supports the requirement to avoid losing requests. API Gateway can integrate with AWS services, including SQS, to accept requests from mobile and web clients. The ALB options do not provide the same durable buffering, and the SNS option is less appropriate because the key requirement is loose coupling with durable request preservation. Therefore,Bis the strongest design. (AWS Documentation)