DVA-C02 Troubleshooting and Optimization Practice Question
This DVA-C02 practice question tests your understanding of troubleshooting and optimization. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 developer is troubleshooting a slow Amazon DynamoDB table. The table has a read capacity of 1000 RCU and a write capacity of 500 WCU. The application frequently reads the same item. Which TWO actions can improve read performance?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Implement DynamoDB Accelerator (DAX) for caching.
Option D is correct because DynamoDB Accelerator (DAX) is an in-memory cache that can reduce read latency for frequently accessed items from milliseconds to microseconds, offloading read traffic from the table and improving performance without requiring a capacity increase. Option E is correct because eventually consistent reads consume half the RCU of strongly consistent reads (0.5 RCU vs 1 RCU per 4 KB item) and return data faster, which is suitable when the application can tolerate slightly stale data for the same item.
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.
✗
Increase the read capacity units (RCU) to 2000.
Why it's wrong here
Increasing RCU helps if throttling occurs, but the issue is not necessarily throttling.
✗
Add a Global Secondary Index (GSI) on the frequently read attribute.
Why it's wrong here
GSI adds overhead and may increase latency.
✗
Decrease the write capacity units (WCU) to 250.
Why it's wrong here
This does not affect read performance.
✓
Implement DynamoDB Accelerator (DAX) for caching.
Why this is correct
DAX caches reads, reducing latency.
Related concept
Read the scenario before looking for a memorised answer.
✓
Use eventually consistent reads instead of strongly consistent reads.
Why this is correct
Eventually consistent reads use half the RCU and are faster.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose to increase RCU (Option A) as a knee-jerk reaction to slow reads, overlooking that caching (DAX) and consistency model changes are more cost-effective and targeted solutions for repeated reads of the same item.
Detailed technical explanation
How to think about this question
DAX acts as a write-through cache that automatically populates on read misses and invalidates on writes, ensuring consistency for eventually consistent reads while reducing the load on the table's partitions. Eventually consistent reads leverage DynamoDB's distributed replication across multiple storage nodes, returning data from the fastest replica, which typically completes in under one second. In practice, a hot item read repeatedly can cause a 'hot partition' where a single partition's throughput is exhausted, and DAX mitigates this by serving reads from memory rather than the partition.
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 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
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.
Troubleshooting and Optimization — This question tests Troubleshooting and Optimization — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Implement DynamoDB Accelerator (DAX) for caching. — Option D is correct because DynamoDB Accelerator (DAX) is an in-memory cache that can reduce read latency for frequently accessed items from milliseconds to microseconds, offloading read traffic from the table and improving performance without requiring a capacity increase. Option E is correct because eventually consistent reads consume half the RCU of strongly consistent reads (0.5 RCU vs 1 RCU per 4 KB item) and return data faster, which is suitable when the application can tolerate slightly stale data for the same item.
What should I do if I get this DVA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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