Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A developer is troubleshooting an application that uses Amazon ElastiCache for Redis to improve performance. The application periodically experiences high latency during peak hours. The developer checks the ElastiCache metrics and sees that the 'Evictions' metric is consistently high and the 'CacheHitRate' metric is low. The cluster has a single node with a cache.t3.small instance type. Which action will most likely improve the cache hit rate and reduce latency?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
Scale up to a larger node type (e.g., cache.t3.medium) to increase available memory.
Increasing memory reduces the need for evictions, allowing more data to remain in cache, which improves the cache hit rate and reduces latency.
B
Distractor review
Enable cluster mode and distribute data across multiple shards to reduce memory pressure.
Cluster mode can help distribute memory, but it is more complex. For a single-node cluster, scaling up is the more direct solution. However, this option is plausible, but the most likely first step is to scale up the instance.
C
Distractor review
Change the eviction policy to 'allkeys-lfu' to better manage which keys are evicted.
Changing the eviction policy can improve the quality of evictions (e.g., keep frequently used keys), but if the memory is full, evictions will still occur. This may help the hit rate but not as effectively as adding memory.
D
Distractor review
Add a read replica for the Redis cluster to offload read traffic.
Read replicas help with read throughput but do not increase memory capacity. Evictions occur on the primary node, so a replica does not solve the memory shortage.
Common exam trap
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Technical deep dive
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- 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.
Related practice questions
Related DVA-C02 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A developer is building a REST API using Amazon API Gateway that will serve static content from an Amazon S3 bucket. The API should cache responses for frequently accessed objects to reduce latency. Which API Gateway feature should the developer enable?
Question 2
A developer is running a web application on multiple Amazon EC2 instances behind an Application Load Balancer (ALB). The application needs to store user session state that must be available across all instances. The session data is small and temporary but must survive individual instance failures. Which AWS service should the developer use to store this session state?
Question 3
A developer has an AWS Lambda function that processes messages from an Amazon SQS standard queue. The function is idempotent and currently has a batch size of 10. The developer wants to increase throughput and increases the batch size to 100. After the change, CloudWatch metrics show a significant increase in throttles and the queue backlog is growing. The function's reserved concurrency is set to 10. What is the most effective action to resolve the throttling and improve throughput?
Question 4
A developer is managing an application running on Amazon EC2 instances behind an Application Load Balancer. Users report that the application becomes unresponsive after several hours, and restarting the instance temporarily fixes the issue. The developer suspects a memory leak but cannot add custom instrumentation. Which AWS service can collect memory utilization metrics and help identify the memory leak with minimal configuration?
Question 5
A developer is building a serverless web application using AWS Lambda and Amazon DynamoDB. The application needs to perform complex aggregations on data stored in DynamoDB. Which AWS service should the developer use to perform these aggregations efficiently without reading all the data into Lambda?
Question 6
A developer has an Amazon S3 bucket containing private user documents. The application must generate a time-limited URL for users to download their own documents without requiring the users to have AWS credentials. Which solution should the developer use?
FAQ
Questions learners often ask
What does this DVA-C02 question test?
Read the scenario before looking for a memorised answer.
What is the correct answer to this question?
The correct answer is: Scale up to a larger node type (e.g., cache.t3.medium) to increase available memory. — High evictions indicate that the cache memory is full, and Redis is evicting keys to make room for new writes. A low cache hit rate suggests that frequently accessed data is being evicted, leading to more reads from the database, which causes high latency. The most effective solution is to increase the memory capacity of the cluster, either by scaling up to a larger node type or by adding more shards (cluster mode enabled). Option A (enabling cluster mode) adds complexity but can help distribute data; however, for a single node, scaling up is simpler. Option B (adjusting eviction policy) might help but does not solve the memory shortage. Option C (adding a read replica) does not increase memory capacity for the primary node. Option D (enabling encryption) does not improve performance.
What should I do if I get this DVA-C02 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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