**To update the mapping between an event source and an AWS Lambda function** The following ``update-event-source-mapping`` example updates the batch size to 8 in the specified mapping. :: aws lambda update-event-source-mapping \ --uuid "a1b2c3d4-5678-90ab-cdef-11111EXAMPLE" \ --batch-size 8 Output:: { "UUID": "a1b2c3d4-5678-90ab-cdef-11111EXAMPLE", "StateTransitionReason": "USER_INITIATED", "LastModified": 1569284520.333, "BatchSize": 8, "State": "Updating", "FunctionArn": "arn:aws:lambda:us-west-2:123456789012:function:my-function", "EventSourceArn": "arn:aws:sqs:us-west-2:123456789012:mySQSqueue" } For more information, see `AWS Lambda Event Source Mapping <https://docs.aws.amazon.com/lambda/latest/dg/invocation-eventsourcemapping.html>`__ in the *AWS Lambda Developer Guide*.