You can generally get the best overall feed processing performance by following these guidelines:
To help ensure that updates occur in the order feeds are uploaded, we generally separate feeds by type, and then process them sequentially, except as noted below.
For tab-delimited text-file feeds, each seller's feeds are separated into the following types and processed one at a time within each type, except as noted:
For XML feeds, each seller's feeds are separated into the following types and processed one at a time within each type, except as noted:
Different feed type
If you submit multiple feeds of the same type (except refunds), they will generally be processed in succession. However, feeds of different types can process at the same time. For example, if you submit 10 listing feeds and then submit one shipping confirmation feed, the shipping confirmation feed may begin processing before the listing feeds are done processing.
Here are the basic feed processing steps for every feed you upload:
One key to maximizing the overall performance of your feeds is reducing the number of times steps 1, 2, and 4 happen for your feeds as a whole. Each step adds to processing time, and step 2 can take as long for a small feed as it does for a larger feed.