SAA-C03 Design High-Performing Architectures Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Publish a version of the function and configure provisioned concurrency on an alias, using autoscaling for the alias.

  Why this is correct

  Provisioned concurrency pre-initializes execution environments for a specific published function version. By attaching provisioned concurrency to an alias, you can control warm capacity and (with the right settings) autoscale the provisioned capacity for predictable spike patterns, reducing cold-start-driven latency increases.

• ✗

  Increase the function memory size and rely on faster initialization to reduce cold starts.

  Why it's wrong here

  Allocating more memory to the Lambda function increases the proportional CPU allocation and can shorten the time needed for certain CPU-bound initialization tasks, such as loading libraries or connecting to databases. However, memory does not pre-provision any execution environments, so during a sharp traffic spike each new concurrent invocation still requires a full cold start—including container spin-up, runtime bootstrapping, and code download—which remains unpredictable. The option also lacks any mechanism to scale warm capacity with demand, so it does not address the specific latency spike pattern the team is trying to eliminate.

  When this WOULD be correct

  A question where the goal is to reduce the duration of cold starts (e.g., 'Which configuration minimizes the impact of cold starts on latency?') and the candidate is constrained from using provisioned concurrency due to cost or other restrictions.

• ✗

  Set reserved concurrency equal to the expected peak requests per second for the function.

  Why it's wrong here

  Setting reserved concurrency to match expected peak requests per second does not warm any execution environments; it merely defines an upper bound on the number of simultaneous invocations for the function and reserves that capacity against other functions in the account. In fact, if the reserved concurrency value is still lower than the actual burst of concurrent requests, lambda will throttle new invocations, causing request failures rather than preventing cold starts. Reserved concurrency is a governance and throttling control, not a way to maintain pre-initialized runtime instances, so it leaves the cold-start latency problem entirely unresolved.

  When this WOULD be correct

  In a scenario where a Lambda function must not exceed a specific concurrency limit to avoid throttling downstream resources (e.g., a database with connection limits), and the goal is to cap concurrent invocations rather than reduce latency.

• ✗

  Use an event source mapping with a higher batch size so Lambda triggers earlier and keeps the runtime warm.

  Why it's wrong here

  Event source mappings apply to event sources such as SQS, Kinesis, or DynamoDB streams. For an ALB-triggered Lambda (synchronous request/response), batch size is not a mechanism to guarantee warm environments or to mitigate cold starts.

  When this WOULD be correct

  For a Lambda function processing messages from an SQS queue or DynamoDB Streams, increasing the batch size can reduce the number of invocations and keep the runtime warm by processing more records per invocation, thereby mitigating cold starts during traffic spikes.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The SAA-C03 exam frequently reuses these exact scenarios with slightly different constraints.

Analysis generated from the official SAA-C03blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

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