The batching window reaches its maximum value. Batching window behavior varies depending on the specific event source.

For Kinesis, DynamoDB, and Amazon SQS event sources: The default batching window is 0 seconds. This means that Lambda sends batches to your function as quickly as possible. If you configure a MaximumBatchingWindowInSeconds, the next batching window begins as soon as the previous function invocation completes.

For Amazon MSK, self-managed Apache Kafka, and Amazon MQ event sources: The default batching window is 500 ms. You can configure MaximumBatchingWindowInSeconds to any value from 0 seconds to 300 seconds in increments of seconds. A batching window begins as soon as the first record arrives.

Note

Because you can only change MaximumBatchingWindowInSeconds in increments of seconds, you cannot revert back to the 500 ms default batching window after you have changed it. To restore the default batching window, you must create a new event source mapping.

The batch size is met. The minimum batch size is 1. The default and maximum batch size depend on the event source. For details about these values, see the BatchSize specification for the CreateEventSourceMapping API operation.

The payload size reaches 6 MB. You cannot modify this limit.

https://docs.aws.amazon.com/lambda/latest/dg/invocation-eventsourcemapping.html