Migration from DDB stream to Kinesis Data Stream

Question

Situation
- There are 2 Lambda functions subscribing an active DDB stream from a DDB table.
- I found that I can subscribe at most 2 lambda functions for a DDB stream.
- So I want to migrate event streaming service from DDB stream to Kinesis data stream with existing lambda.

Questions
- Do I have to create a replica for the existing lambda to connect Kinesis data stream? A single lambda function can subscribe both DDB stream and Kinesis data stream?
- Does a single table can publish event to both DDB stream and Kinesis at the same moment?
- What is a proper way to migrate from DDB stream to Kinesis data stream?

Thank you.

Buddhike de Silva · Accepted Answer

Hi Wade,
Thanks for sharing your question here.

DDB has a built-in mechanism to publish changes to a Kinesis data stream. Please [see this guide](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/kds.html) for more information.

You can have both DDB stream and KDS integration on in your DDB table.

You should be able to have multiple triggers configured for your Lambda. However, I think the event format published from various sources may vary and therefore you may have to handle it in your Lambda code.

Easiest way to use KDS with DDB is to use the built-in integration. However, your records may appear out of order and also there might be duplicates. Consider how this impacts your application and see if you can implement the workarounds suggested in the documentation.

Migration from DDB stream to Kinesis Data Stream

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