Quick Answer
The answer is Amazon DAX, the DynamoDB Accelerator, because it is an in-memory cache built specifically to reduce DynamoDB read latency for repeated, identical read requests. When a mobile app fetches the same product details many times per minute, DAX intercepts those reads and serves them from its ultra-fast cache, cutting latency from single-digit milliseconds down to microseconds. On the SAA-C03 exam, this scenario tests your understanding of caching strategies for read-heavy workloads, and it often appears alongside traps like ElastiCache (which is generic and requires more management) or DynamoDB Global Tables (which solve regional latency, not repeated reads). The key distinction is that DAX is purpose-built for DynamoDB and handles cache invalidation automatically. Memory tip: think of DAX as a “DynamoDB Accelerator” that makes repeated reads “dash” fast, just like the name implies.
This SAA-C03 practice question tests your understanding of design secure architectures. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
A mobile app reads the same product details many times per minute from Amazon DynamoDB. The table design is already correct, but repeated reads are still causing noticeable latency. Which service should the team add to improve read performance?
Amazon DAX
DAX adds an in-memory cache in front of DynamoDB to reduce read latency for repeated accesses.
Amazon EFS
Why wrong: EFS is a shared file system and does not accelerate DynamoDB read operations.
AWS Lambda
Why wrong: Lambda is a compute service and does not provide caching for DynamoDB reads.
Amazon SNS
Why wrong: SNS is used for pub/sub messaging and does not reduce latency for repeated database reads.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Amazon DAX
Amazon DAX (DynamoDB Accelerator) is an in-memory cache specifically designed for DynamoDB. It reduces read latency from single-digit milliseconds to microseconds by caching frequently accessed items, which directly addresses the repeated read pattern described in the question.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Amazon DAX
Why this is correct
DAX adds an in-memory cache in front of DynamoDB to reduce read latency for repeated accesses.
Related concept
Read the scenario before looking for a memorised answer.
Amazon EFS
Why it's wrong here
EFS is a shared file system and does not accelerate DynamoDB read operations.
AWS Lambda
Why it's wrong here
Lambda is a compute service and does not provide caching for DynamoDB reads.
Amazon SNS
Why it's wrong here
SNS is used for pub/sub messaging and does not reduce latency for repeated database reads.
Common exam traps
The trap here is that candidates may confuse DAX with ElastiCache (which is generic and not DynamoDB-native) or assume that Lambda or SNS can somehow accelerate reads, but DAX is the only service purpose-built for DynamoDB read acceleration.
Detailed technical explanation
DAX maintains a write-through cache that synchronizes with DynamoDB, so reads for cached items bypass the DynamoDB storage engine entirely. Under the hood, DAX uses a cluster of nodes with in-memory caches that support item-level and query/scan caching, and it automatically invalidates stale data based on TTL or write operations. In a real-world scenario, a mobile app fetching product details thousands of times per minute would see latency drop from ~5 ms to under 1 ms with DAX, while also reducing DynamoDB read capacity unit consumption.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
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FAQ
Design Secure Architectures — This question tests Design Secure Architectures — Read the scenario before looking for a memorised answer..
The correct answer is: Amazon DAX — Amazon DAX (DynamoDB Accelerator) is an in-memory cache specifically designed for DynamoDB. It reduces read latency from single-digit milliseconds to microseconds by caching frequently accessed items, which directly addresses the repeated read pattern described in the question.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 2026
This SAA-C03 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SAA-C03 exam.
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