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Answer: Configure Amazon DynamoDB Accelerator (DAX) for the new messages table. Update the code to use the DAX endpoint.
## Explanation **Correct Answer: A** Amazon DynamoDB Accelerator (DAX) is specifically designed for this use case. Here's why: ### Why DAX is the best solution: 1. **Minimal latency**: DAX provides microsecond latency for read operations by caching frequently accessed data in memory. 2. **Minimal application changes**: The application only needs to change the endpoint from DynamoDB to DAX - DAX is fully compatible with DynamoDB API calls. 3. **Seamless integration**: DAX sits between the application and DynamoDB, automatically caching read responses and handling cache invalidation. 4. **Optimized for DynamoDB**: DAX is purpose-built for DynamoDB, providing better performance than generic caching solutions. ### Why other options are not optimal: **B. DynamoDB read replicas**: - Global Tables (read replicas) are for geographic distribution, not primarily for latency reduction - They still have DynamoDB latency characteristics (single-digit milliseconds) - More complex to manage than DAX **C. Doubling read capacity units**: - This only addresses throughput, not latency - DynamoDB latency is generally consistent regardless of provisioned capacity - Does not provide the microsecond latency users want **D. ElastiCache for Redis**: - Requires significant application changes (different API, cache invalidation logic) - Application needs to implement cache-aside pattern manually - More complex to implement and maintain than DAX - Not purpose-built for DynamoDB ### Key Benefits of DAX: - **In-memory caching**: Provides microsecond read latency - **API compatibility**: Uses the same API as DynamoDB - **Write-through caching**: Automatically invalidates cache on writes - **Managed service**: AWS handles scaling, patching, and maintenance - **Minimal code changes**: Just change the endpoint in your application For a chat application where users expect near-real-time message delivery, DAX provides the optimal balance of low latency and minimal application changes.
Author: LeetQuiz Editorial Team
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A company has a mobile chat application with a data store based in Amazon DynamoDB. Users would like new messages to be read with as little latency as possible. A solutions architect needs to design an optimal solution that requires minimal application changes.
Which method should the solutions architect select?
A
Configure Amazon DynamoDB Accelerator (DAX) for the new messages table. Update the code to use the DAX endpoint.
B
Add DynamoDB read replicas to handle the increased read load. Update the application to point to the read endpoint for the read replicas.
C
Double the number of read capacity units for the new messages table in DynamoDB. Continue to use the existing DynamoDB endpoint.
D
Add an Amazon ElastiCache for Redis cache to the application stack. Update the application to point to the Redis cache endpoint instead of DynamoDB.