According BCS architecture
there is a model metadata caching. Sometimes, after updating model (by Central
Administration, or provisioning by farm scope feature there is a bug occurring
when external list is being viewed – loading icon always showing.
This happens when the parameters of connection to the database changed
in the model because of some problem in the metadata model caching.
To fix this bug - it is necessary with the Sharepoint Designer to change
connection settings (for example Authentication Mode), save and then return all
back. This manipulation will reset the cache. Don’t forget about one minute:
BDC caches the objects when they first load. A timer running on each server looks for any changes to the metadata objects one time each minute. If it sees a change to a metadata object, it clears the cache and then reloads it. As a result, after you change metadata, you must wait up to a minute for changes to propagate to all the servers in the farm. The changes are immediate on the server where you make the change.
