FTP feeds are processed immediately upon receipt. Generally, it takes a few minutes for the feed to be processed, ingested into our system, and distributed to our servers.
A "full" or "sync" feed will replace any existing product data currently in our system. That is, new products in the feed will be added, products that are no longer in the feed will be removed, and products with changes will be updated.
A "delta" feed only updates those products or variations sent in the feed. All information about the product or variation should be sent, even if only a subset is updated.
We will automatically fail ingestions that would remove many products (currently defined as 50% of catalog). To override this behavior, send the catalog with the filename keywords forcedelta or forcesync.