You can upload or download a large object as a set of multiple independent parts.
Amazon Redshift Connector uses the AWS TransferManager API to upload a large object in multiple parts to Amazon S3. While downloading a large object, the Secure Agent downloads the object in multiple parts from the Amazon S3.
When the file size is more than 5 MB, you can configure multipart upload to upload object in multiple parts in parallel. You can choose to download the object in multiple parts in parallel when the file size of an Amazon S3 object is greater than 12 MB.
You can configure Enable Downloading S3 Files in Multiple Parts option in the advanced source properties. You can configure the Part Size and TransferManager Thread Pool Size options in the advanced target properties.