title: Sequence constraints of product feeds for Amazon MWS
body: <p>I am currently working on a specification for a software component which will synchronize the product catalog of an ecommerce company with the Amazon Marketplace using Amazon MWS.</p>
  
  <p>According to the MWS developer documentation, publishing products requires submitting up to 6 different feeds, which are processed asynchronously:</p>
  
  <ul>
  <li><strong>Product Feed:</strong> defines SKUs and contains descriptive data for the products</li>
  <li><strong>Inventory Feed:</strong> sets quantities/availability for each SKU</li>
  <li><strong>Price Feed:</strong> sets prices for SKUs</li>
  <li><strong>Image Feed:</strong> product images for each SKU</li>
  <li><strong>Relationship Feed:</strong> defines mappings between parent SKUs (e.g. a T-Shirt) and child SKUs (e.g. T-Shirt in a concrete size and color which is buyable)</li>
  <li>Ovverride Feed:</li>
  </ul>
  
  <p>My question concerns the following passage in the MWS documentation:</p>
  
  <blockquote>
    <p>The Product feed is the first step in setting up your products on
    Amazon. All subsequent catalog feeds are dependent upon the success of
    this feed.</p>
  </blockquote>
  
  <p>I am wondering what it means? There are at least two possibilities:</p>
  
  <ul>
  <li><p><em>Do you have to wait until the Product feed is successfully processed before submitting subsequent feeds?</em> This would mean that one had to request the processing state periodically until it is finished. This may take hours depending of the feed size and server load at Amazon. The process of synchronizing products would be more complex.</p></li>
  <li><p><em>Can you send all the feeds immediately in one sequence</em> and Amazon takes care that they are processed in a reasonable order?  In this interpretation, the documentation would just tell the obvious, that the success of let's say image feed processing for a particular SKU depends on the success of inserting the SKU itself.</p></li>
  </ul>