2.1.4.4. DynamoDB Streams & Triggers

2.1.4.4. DynamoDB Streams & Triggers

First Principle: DynamoDB Streams capture item-level changes in real time, enabling developers to build event-driven applications that react to data modifications and foster loose coupling.

Amazon DynamoDB Streams is an AWS service that captures a time-ordered sequence of item-level modifications in an Amazon DynamoDB table. Every modification (creation, update, deletion) to an item in a DynamoDB table is captured as a data record in the stream.

• Real-time Changes: Captures every item-level modification in chronological order.
• Event Source: DynamoDB Streams can be configured as an event source for AWS Lambda functions.
• Lambda Triggers: A Lambda function can be automatically invoked (triggered) whenever new records are written to a DynamoDB Stream.
• Use Cases:
  • Real-time Analytics: Process data changes for immediate insights.
  • Data Synchronization: Propagate changes to other data stores (e.g., full-text search index, data warehouse).
  • Auditing: Maintain a complete log of all data modifications.
  • Event-Driven Microservices: Build applications that react to specific data changes.

Scenario: You're developing a social media application that stores user posts in a DynamoDB table. When a new post is created, you need to automatically trigger two separate processes: one to moderate the content and another to update a search index.

⚠️ Exam Trap: DynamoDB Streams records are available for 24 hours, not indefinitely. If a question asks about processing older changes, DynamoDB Streams won't help — you'd need Kinesis Data Streams with longer retention.