How change the "batch size" of a AWS Lambda MSK Event source

Question

I created an MSK Cluster and a Lambda Function I want to be triggered when there are new events on the events on the MSK Cluster.

I created the event source, and it says:

Batch size: 100

I want a lower Batch size, but I cannot find any way to change it. Not via CLI and not via the AWS web interface.

Answer 1

You can use the create-event-source-mapping or update-event-source-mapping API. Both have a batch size option where you can set that up:

--batch-size (integer)

The maximum number of items to retrieve in a single batch. Amazon Managed Streaming for Apache Kafka - Default 100. Max 10,000.