DynamoDB Streams, DAX, and Scalability

Get an overview of DynamoDB streams and DAX.

DynamoDB Streams

DynamoDB Streams help you keep a list of item level changes or provide a list of item level changes that have taken place in the last 24 hours.

  • Amazon DynamoDB is integrated with AWS Lambda so that you can create triggers which are pieces of code that automatically respond to events in DynamoDB Streams.
  • If you enable DynamoDB Streams on a table, you can associate the stream ARNAmazon Resource Names with a Lambda function that you write.

Dynamo DAX

Amazon DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache for DynamoDB that delivers up to a 10x performance improvement. It improves performance from milliseconds to microseconds, even at millions of requests per second.

DAX does all the heavy lifting required to add in-memory acceleration to your DynamoDB tables without requiring developers to manage cache invalidation, data population, or cluster management. You do not need to modify application logic since DAX is compatible with existing DynamoDB API calls.

You can enable DAX with just a few clicks in the AWS Management Console or using the AWS SDK.

Charges

  • As with DynamoDB, you only pay for the capacity you provision.

  • Provisioned through clusters are charged by the node (runs on EC2 instances).

  • Pricing is per node-hour consumed and is dependent on the instance type you select.

The following diagram depicts the Amazon DynamoDB DAX service:

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