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Difficulty: EasyApplication Caching and Session State Management

An application uses Amazon DynamoDB to store active user session data. During peak traffic hours, the application experiences latency spikes when retrieving session states. Which of the following are recommended best practices to optimize performance and prevent session state retrieval bottlenecks? (Select TWO)

  1. Enable DynamoDB Accelerator (DAX) to cache session data and provide microsecond read latency.Answer
  2. Design partition keys with high entropy, such as a unique session ID, to distribute read and write operations evenly across partitions.Answer
  3. C
    Store user session data in Systems Manager Parameter Store and enable automatic rotation of session parameters.
  4. D
    Perform a Scan operation with a filter expression on a custom session attribute to locate active session records.
  5. E
    Scale up the table's overall provisioned read capacity units (RCUs) immediately upon encountering a ProvisionedThroughputExceededException.

Answer

Enable DynamoDB Accelerator (DAX) to cache session data and design partition keys with high entropy, such as a unique session ID, to distribute operations evenly.
Enabling DynamoDB Accelerator (DAX) provides an in-memory cache that reduces read latency to microseconds. Additionally, designing high-entropy partition keys ensures even request distribution, which prevents hot partitions and scaling bottlenecks.

Step-by-Step Solution

1
Analyze the workload requirements for user session data stored in Amazon DynamoDB, identifying that the latency spikes occur during read retrieval operations.
Identify that read-heavy workloads with strict latency requirements can benefit from caching.
This establishes that adding a dedicated caching layer like DynamoDB Accelerator (DAX) is the appropriate performance optimization.
2
Evaluate partition key design to ensure write and read distributions are uniform.
Select high-entropy attributes (such as unique session IDs) as partition keys.
Uniform key distribution prevents hot partitions, which cause ProvisionedThroughputExceededException and latency spikes even when overall capacity seems sufficient.
3
Review and eliminate anti-patterns like using Scan operations or storing session data in SSM Parameter Store.
Avoid full table scans and configuration store misuse.
Scans consume excessive read capacity units, and Parameter Store is not designed for fast, high-volume session data storage.

Key Concept

Caching DynamoDB read requests using DAX and avoiding hot partitions with high-entropy keys.
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Topics

Application Caching and Session State Management

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