InvalidationBatch (string)

A value that you specify to uniquely identify an invalidation request. CloudFront uses the value to prevent you from accidentally resubmitting an identical request. Whenever you create a new invalidation request, you must specify a new value for CallerReference and change other values in the request as applicable. One way to ensure that the value of CallerReference is unique is to use a timestamp, for example, 20120301090000. If you make a second invalidation request with the same value for CallerReference, and if the rest of the request is the same, CloudFront doesn't create a new invalidation request. Instead, CloudFront returns information about the invalidation request that you previously created with the same CallerReference. If CallerReference is a value you already sent in a previous invalidation batch request but the content of any Path is different from the original request, CloudFront returns an InvalidationBatchAlreadyExists error.