the essence of the question at this point is FE "Farms" i.e. one
per user ; kept on the BE server - - rather than putting them on
the user's desktop
from all the input I believe that the impact is "only" the initial
download of the application ("only" : that could be a big impact
if the FE is big and there are alot of users)
No, you're wrong -- it is *not* just the initial download. Locks
have to be maintained across the network (when your user front end
is opened there will be an LDB file created), and certain kinds of
operations save data back to the file, such as closing a form to
which a sort or filter has been applied (i.e., the sort order/filter
gets saved).
Likewise, a front end is a Jet database, and Jet always retrieves
only as much as it needs. Now, an Access front end is all stored as
part of the Access project in a single binary BLOB field in one of
the system tables, but my bet is that Microsoft has optimized the
retrieval of that data and does not retrieve all of it at once (it
*is* going to be stored in many different data pages, so,
theoretically, a map of the BLOB field at the head of the BLOB data
could be used to tell Jet how to retrieve only needed data pages).
So, you may end up with multiple trips back to the server just to
retrieve new items that have not previously been opened.
There will definitely be trips back to the server for locking (once
per second, BTW) as well as for saving sort/filters when forms are
closed.
So, again, I'd say your assumption that the performance hit occurs
only once is simply mistaken.
