Subject: RE: Is this really an LCUP show stopper?

From: "Jeff Parham" <[email-masked]>
Date: Thu, 5 Jun 2003 11:06:35 -0700

> Jonghyuk Choi wrote:
> >
> > Because even a single omission of delete / modify in history can
make
> > it impossible to recreate the previous sync result the cookie of a
sync
> > request refers to, it looks more like a matter of how long the full
> > history information is maintained rather than how complete the
history
> > information is.
> 
> LCUP does not require that the server be able to "recreate the
previous
> sync result." It requires that the server be able to, based on the
> cookie supplied by the client, generate a set of Sync Update messages
> that allow the client to synchronize with the server. This is a subtle
> difference, but important in some scenarios.

Mark is correct.  It is not necessary that the server infer the exact
state of the client, just a sufficiently close approximation to ensure
it can send the necessary update messages to bring the client up to
date.  I believe it to be exceedingly rare in practice that strictly
unnecessary transmissions (unnecessary if the server could infer the
exact client state) will be present and consume any significant amount
of resources compared to the strictly necessary transmissions.
Eliminating all strictly unnecessary traffic is unrealistic given the
"no server-side, per-client state" requirement -- at best, you can shift
it around.  For example, LDAP Content Sync's stream of entryUUIDs for
entries already present on the client can be construed as "strictly
unnecessary transmissions".

-J