Stream processing patterns in DynamoDB

Introduction

Stream processing patterns help you react quickly to changes in your database. They let you handle data updates as they happen, like a real-time alert system.

You want to update a search index whenever data changes.

You need to send notifications when a new item is added.

You want to keep data in sync between different systems automatically.

You want to analyze data changes for trends or monitoring.

You want to archive or backup data changes continuously.

Syntax

DynamoDB

No direct query syntax; stream processing uses DynamoDB Streams with AWS Lambda functions to react to data changes.

DynamoDB Streams capture item-level changes in your table.

You connect a Lambda function to the stream to process these changes automatically.

Examples

This setup lets your Lambda function receive new or changed items as events.

DynamoDB

1. Enable DynamoDB Streams on your table with NEW_IMAGE option.
2. Create a Lambda function to process stream records.
3. Configure the Lambda trigger to listen to the DynamoDB Stream.

This code logs new items added to the table.

DynamoDB

Example Lambda event handler snippet (Node.js):
exports.handler = async (event) => {
  for (const record of event.Records) {
    if (record.eventName === 'INSERT') {
      console.log('New item added:', record.dynamodb.NewImage);
    }
  }
};

Sample Program

This query shows current data. Stream processing happens outside SQL by reacting to changes.

DynamoDB

-- DynamoDB Streams setup is done in AWS Console or CLI, no SQL query.
-- Example: Query to get current items from table:
SELECT * FROM YourTable;

Important Notes

Stream processing is event-driven, not a query you run directly.

Remember to handle retries and errors in your Lambda function to avoid data loss.

Streams keep data for 24 hours, so process events quickly.

Summary

Stream processing lets you react to data changes in real time.

Use DynamoDB Streams with Lambda functions to implement these patterns.

This helps automate tasks like notifications, syncing, and analytics.