The answer is to add a DynamoDB Accelerator (DAX) cluster in front of the table and point the application to the DAX endpoint. DAX is a fully managed, in-memory cache that reduces read latency from single-digit milliseconds to microseconds, directly addressing the need to minimize latency and reduce pressure on DynamoDB for the 80% of reads hitting only 200 hot keys. Since the business tolerates data that is a few seconds stale, DAX’s default 5-minute TTL (configurable lower) is perfectly acceptable. On the SAA-C03 exam, this scenario tests your ability to distinguish DAX from ElastiCache or DynamoDB global tables—DAX is the only service purpose-built for DynamoDB read-heavy workloads with eventual consistency. A common trap is choosing ElastiCache, but DAX handles cache invalidation and writes automatically, while ElastiCache requires manual application logic. Memory tip: DAX = DynamoDB Accelerator for eXpress reads.
SAA-C03 Design High-Performing Architectures Practice Question
This SAA-C03 practice question tests your understanding of design high-performing architectures. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
Load-test observations:
- DynamoDB table type: on-demand
- Primary access pattern: GetItem for 200 hot keys
- p95 latency without cache: 17-24 ms
- p95 latency under burst: 31 ms and rising
- Sample application note: "A few seconds of staleness is acceptable for dashboards and recommendations"
- CloudWatch: ConsumedReadCapacityUnits spikes during refresh cycles
Based on the exhibit, a retail analytics service repeatedly reads the same DynamoDB items during an active campaign. The business can tolerate data that is a few seconds stale, but the application must minimize latency and reduce pressure on DynamoDB. A load test shows that 80% of reads target only 200 item keys. What should the solutions architect implement?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "minimum / minimize"
Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
Load-test observations:
- DynamoDB table type: on-demand
- Primary access pattern: GetItem for 200 hot keys
- p95 latency without cache: 17-24 ms
- p95 latency under burst: 31 ms and rising
- Sample application note: "A few seconds of staleness is acceptable for dashboards and recommendations"
- CloudWatch: ConsumedReadCapacityUnits spikes during refresh cycles
A
Add a DynamoDB Accelerator (DAX) cluster in front of the table and point the application to the DAX endpoint.
DAX is purpose-built for DynamoDB read caching and can absorb repeated reads for the same keys with very low latency. Because the workload can tolerate slight staleness, DAX fits the requirement well and reduces pressure on the table during bursts.
B
Switch the table to provisioned capacity with auto scaling so DynamoDB can handle the repeated reads more efficiently.
Why wrong: Provisioned capacity can help with throughput planning, but it does not cache repeated reads or materially reduce read latency for hot items.
C
Create a global table in a second Region and read from the replica Region to lower latency.
Why wrong: Global tables are for multi-Region replication and availability, not for caching repeated reads of the same items in one workload.
D
Move the hot items into Amazon ElastiCache for Redis and keep the remaining data in DynamoDB.
Why wrong: Redis can cache data, but it adds more application design and synchronization work than DAX, which is the native DynamoDB acceleration service.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add a DynamoDB Accelerator (DAX) cluster in front of the table and point the application to the DAX endpoint.
DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache designed specifically for DynamoDB. It reduces read latency from single-digit milliseconds to microseconds and offloads repeated reads from the table, which directly addresses the requirement to minimize latency and reduce pressure on DynamoDB. Since the business can tolerate stale data (DAX default TTL is 5 minutes, but can be configured lower), DAX is ideal for the 80% of reads hitting only 200 hot keys.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Add a DynamoDB Accelerator (DAX) cluster in front of the table and point the application to the DAX endpoint.
Why this is correct
DAX is purpose-built for DynamoDB read caching and can absorb repeated reads for the same keys with very low latency. Because the workload can tolerate slight staleness, DAX fits the requirement well and reduces pressure on the table during bursts.
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Switch the table to provisioned capacity with auto scaling so DynamoDB can handle the repeated reads more efficiently.
Why it's wrong here
Provisioned capacity can help with throughput planning, but it does not cache repeated reads or materially reduce read latency for hot items.
✗
Create a global table in a second Region and read from the replica Region to lower latency.
Why it's wrong here
Global tables are for multi-Region replication and availability, not for caching repeated reads of the same items in one workload.
✗
Move the hot items into Amazon ElastiCache for Redis and keep the remaining data in DynamoDB.
Why it's wrong here
Redis can cache data, but it adds more application design and synchronization work than DAX, which is the native DynamoDB acceleration service.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may choose ElastiCache (Option D) because it is a general-purpose cache, but they overlook that DAX is purpose-built for DynamoDB and eliminates the need for custom cache invalidation and dual-write logic, making it the simpler and more efficient solution for this exact use case.
Detailed technical explanation
How to think about this question
DAX maintains a write-through cache that is updated synchronously on writes, ensuring strong consistency for cached items. Under the hood, DAX uses a cluster of nodes with a primary node handling writes and replicas for read scaling, and it supports item-level caching with a configurable TTL. In a real-world scenario, a retail analytics service with a flash sale campaign would see DAX absorb the repeated reads on the 200 hot keys, reducing DynamoDB read capacity units consumed by up to 80% and keeping p99 latency under 1 millisecond.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Design High-Performing Architectures — This question tests Design High-Performing Architectures — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Add a DynamoDB Accelerator (DAX) cluster in front of the table and point the application to the DAX endpoint. — DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache designed specifically for DynamoDB. It reduces read latency from single-digit milliseconds to microseconds and offloads repeated reads from the table, which directly addresses the requirement to minimize latency and reduce pressure on DynamoDB. Since the business can tolerate stale data (DAX default TTL is 5 minutes, but can be configured lower), DAX is ideal for the 80% of reads hitting only 200 hot keys.
What should I do if I get this SAA-C03 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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