Intermediate LevelCloud Computing (AWS/GCP/Azure)
How do DynamoDB Streams trigger AWS Lambda functions for real-time Change Data Capture (CDC)?
❓ Interview Prompt: Explain DynamoDB Streams, stream view types (KEYS_ONLY, NEW_IMAGE, OLD_IMAGE, NEW_AND_OLD_IMAGES), and Lambda event source mappings.
DynamoDB Streams captures a time-ordered sequence of item-level modifications (inserts, updates, deletes) in a DynamoDB table in real time.
Stream View Types:
•
'KEYS_ONLY': Logs only the partition/sort keys of modified items.
•
'NEW_IMAGE': Logs the entire item after modification.
•
'OLD_IMAGE': Logs the entire item before modification.
•
'NEW_AND_OLD_IMAGES': Logs both before and after states.
Real-Time CDC Use Cases:
Triggering Lambda functions to update OpenSearch search indexes, send notification emails, or replicate changes to external data lakes.
Code Implementation Example
typescript
import { DynamoDBStreamHandler } from 'aws-lambda';
// Lambda handler processing CDC records from DynamoDB Stream
export const handler: DynamoDBStreamHandler = async (event) => {
for (const record of event.Records) {
if (record.eventName === 'INSERT') {
const newOrder = record.dynamodb?.NewImage;
console.log('New Order Inserted:', newOrder?.OrderId?.S);
// Synchronize to OpenSearch / Cache...
}
}
};💡Lambda function handling Change Data Capture (CDC) events from DynamoDB Stream.
🎯 Interview Key Takeaway
DynamoDB Streams logs item modifications in real time, triggering Lambda functions for event-driven CDC architectures.
#DynamoDB Streams#Lambda#CDC#Event-Driven#Intermediate
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