DAX (DynamoDB Accelerator) caching

Introduction

DAX caching helps your database respond faster by storing data in a quick-access memory. It reduces waiting time when you ask for data.

When your app needs to get data very fast, like a live scoreboard.

When many users ask for the same data often, like product details on a shopping site.

When you want to reduce the cost of database reads by using cached data.

When your database is slow during busy times and you want to speed it up.

When you want to improve user experience by showing data quickly.

Syntax

DynamoDB

Use DAX client in your application code to connect to DAX cluster.
Example in AWS SDK:

const AmazonDaxClient = require('amazon-dax-client');

const dax = new AmazonDaxClient({endpoints: ['mydaxcluster.example.com:8111'], region: 'us-west-2'});

// Use dax client like DynamoDB client
const params = { TableName: 'MyTable', Key: { id: { S: '123' } } };
const result = await dax.getItem(params).promise();

DAX is a separate caching service that sits between your app and DynamoDB.

You use a special DAX client instead of the normal DynamoDB client in your code.

Examples

Get a user item from the DAX cache or DynamoDB if not cached.

DynamoDB

const AmazonDaxClient = require('amazon-dax-client');
const dax = new AmazonDaxClient({endpoints: ['mydaxcluster.example.com:8111'], region: 'us-west-2'});

const params = { TableName: 'Users', Key: { userId: { S: 'user123' } } };
const user = await dax.getItem(params).promise();

Retrieve product details quickly using DAX caching.

DynamoDB

const params = { TableName: 'Products', Key: { productId: { S: 'prod456' } } };
const product = await dax.getItem(params).promise();

Sample Program

This code connects to a DAX cluster and tries to get a book item by its ID. It prints the book data if found.

DynamoDB

const AmazonDaxClient = require('amazon-dax-client');

(async () => {
  const dax = new AmazonDaxClient({endpoints: ['mydaxcluster.example.com:8111'], region: 'us-west-2'});

  const params = {
    TableName: 'Books',
    Key: { bookId: { S: 'book123' } }
  };

  try {
    const data = await dax.getItem(params).promise();
    console.log('Book data:', JSON.stringify(data.Item));
  } catch (err) {
    console.error('Error fetching data:', err);
  }
})();

Important Notes

DAX caches only read operations like GetItem and Query, not writes.

Cache updates happen automatically but may have a small delay.

Using DAX reduces the number of calls directly to DynamoDB, saving cost and time.

Summary

DAX caching makes DynamoDB queries faster by storing data in memory.

Use a special DAX client in your app to connect to the DAX cluster.

DAX is best when many users read the same data often.