title: How to check if my uploaded file is "multipart" or not?
body: <p>From the doc : "When you download a file using TransferManager, the utility automatically determines if the object is multipart"</p>
  
  <p>source : <a href="https://aws.amazon.com/fr/blogs/developer/parallelizing-large-downloads-for-optimal-speed/" rel="nofollow noreferrer">https://aws.amazon.com/fr/blogs/developer/parallelizing-large-downloads-for-optimal-speed/</a></p>
  
  <p>It means there are indicators somewhere (metadata ? properties ?) which can tell you if a file is "multipart". So I'm testing AWS Rest APIs with AWS CLI before testing with java SDK, and i'm focusing on multipart uploads/downloads (according to the doc, a download will be multipart only if the upload was multipart).</p>
  
  <p>First I set the threshold explicitely to 5MB :</p>
  
  <pre><code>$ aws configure set default.s3.multipart_threshold 5MB
  </code></pre>
  
  <p>And I upload a 20 MB file :</p>
  
  <pre><code>$ aws s3 cp ./my-file s3://my-bucket/test/multipart-upload-1
  </code></pre>
  
  <p>It takes 45s, and when I check during upload with :</p>
  
  <pre><code>$ aws s3api list-multipart-uploads --bucket my-bucket
  </code></pre>
  
  <p>I can see my upload is part of the list, but I see only one download and no information about the number of "parts" or connections.</p>
  
  <p>If I set the threshold to 50MB (far over the file size), the upload is much faster (over in 10s) and during the upload I can't see the upload using :</p>
  
  <pre><code>$ aws s3api list-multipart-uploads --bucket my-bucket
  </code></pre>
  
  <p>So it tends to show me the first upload was recognized as a "multipart" upload, but I have no informations about the number of parts and after the upload I can't distinguish between multipart uploaded files and simply uploaded file.</p>