如果AWS Lambda函数具有来自多个Kinesis流的事件源，那么传入记录的批处理将来自单个Kinesis流还是混合源？

Question

The title might be a bit confusing. I'll try my best to make it clearer.

Suppose I have a AWS Lambda function that has two different Kinesis streams A and B as input event sources.

So, for the below, since a KinesisEvent instance contains a batch of records, will the batch contain records from a single stream, or essentially it contain records from both streams A and B?

public class ProcessKinesisEvents {
    public void recordHandler(KinesisEvent event, Context context) {
        ...
    }
}

Answer 1

Each mapping between an AWS Kinesis stream and an AWS Lambda function is a dedicated entity resulting from a call to CreateEventSourceMapping and comprised of the EventSourceArn and the FunctionName , for which you also specify a dedicated Batch Size accordingly:

POST /2015-03-31/event-source-mappings/ HTTP/1.1
Content-type: application/json

{
    "BatchSize": number,
    "Enabled": boolean,
    "EventSourceArn": "string",
    "FunctionName": "string",
    "StartingPosition": "string"
}

Consequently, the batches you will receive are constrained to the single event source that constitutes the resp. mapping, and each other event source will yield a separate invocation of your Lambda function accordingly, so everything is properly isolated.