Multiple users have requested the ability to retrieve multiple "JSON Document Attribute" values from AWS DynamoDB. Currently, the GetDynamoDB processor only allows the retrieval of a single document attribute during invocation.
Possible avenues to implement this include a regex for selecting multiple JSON document attributes or a comma-separated enumerated list. The destination of the data is also a concern – currently the response becomes the flowfile content. If multiple keys are queried, perhaps a nested JSON document would be returned into the flowfile content. Or a new processor GetDynamoDBRecord could be introduced which formats the response into NiFi record elements.