A multi-server application might require locked caching, where only one Oracle ATG Web Commerce instance at a time has write access to the cached data of a given item type. You can use locked caching to prevent multiple servers from trying to update the same item simultaneously—for example, Commerce order items, which can be updated by customers on an external-facing server and by customer service agents on an internal-facing server. By restricting write access, locked caching ensures a consistent view of cached data among all Oracle ATG Web Commerce instances.