DynamoDB Accelerator

In this lesson, we explore AWS DynamoDB Accelerator (DAX), a fully managed, in-memory caching service designed to boost Amazon DynamoDB performance. DAX can improve read performance by up to 10 times, reducing latency from milliseconds to microseconds even when handling millions of requests per second.

DAX Architecture and Workflow

A DAX cluster is composed of one or more nodes. Within the cluster, one node operates as the primary node while any additional nodes act as read replicas. A DAX cluster can include up to 10 nodes (one primary and nine replicas). At runtime, the DAX client transparently redirects all DynamoDB API requests from your application to the DAX cluster, which intelligently manages load balancing and routing among the nodes.

When a get item request is made:

• The DAX client first attempts to serve the request from its in-memory cache.
• If the item is cached, it is returned in microseconds.
• If the item is not in the cache, the request is forwarded to DynamoDB, and the returned data is subsequently cached for future requests.

Scalability and Management

DAX scales on demand. You can start with a modest three-node cluster and add more nodes as your traffic increases, up to the maximum of 10 nodes. Like DynamoDB, DAX is fully managed by AWS, which removes the need to manage the underlying infrastructure manually.

Seamless Integration

One of the major advantages of using DAX is its API compatibility with DynamoDB. To integrate DAX into an existing application, you only need to swap out the standard DynamoDB client with the DAX client—no major code rewrites are required.

Additionally, DAX offers flexible deployment options:

• Provision a single DAX cluster to serve multiple DynamoDB tables.
• Create multiple clusters tailored to a single table, depending on your workload and performance needs.

Integration with AWS Compute Services

DAX integrates effortlessly with various AWS compute services such as AWS Lambda and Amazon EC2. Simply replace your DynamoDB client with the DAX client and your application will benefit from enhanced performance without further modifications.

Operational Efficiency

In summary, DynamoDB Accelerator (DAX) enhances DynamoDB's read performance through an in-memory caching layer that:

• Increases throughput by handling millions of requests per second.
• Reduces latency by caching frequently accessed items.
• Lowers operational costs by offloading read requests from DynamoDB.
• Simplifies application architecture by eliminating the need for custom caching logic.

DAX ensures data consistency and high availability by writing data concurrently to both the cache and the underlying DynamoDB table. This write-through and read-through caching mechanism guarantees that the cached data remains up-to-date.