Re: Applicability of LDAP Content Sync to loosely coupled replica sets

Kurt D. Zeilenga wrote:
> ... However, I was re-reading the draft-ietf-ldup-lcup's
> appendix of features left out of LCUP and came across this statement:
> 
>    The leftSet feature is particularly useful because it indicates to   
>    the client that an entry is no longer within the client's search    
>    specification and the client can remove the associated data from its
>    data store.  Ironically, this feature is the hardest to implement on
>    the server because the server does not keep track of the client's    
>    state and has no easy way of telling which entries moved out of scope
>    between synchronization sessions with the client.  A compromise could
>    be reached by only providing this feature for the operations that    
>    occur while the client is connected to the servers.
> 
> That is, this appendix implies that LCUP's entryLeftSet feature is
> only available during persist mode.  That seems consistent with your
> recent comments in this thread.
> 
> However, this seems quite counter to Section 4.2.7 which implies
> that entryLeftSet is used during incremental synchronization
> and the convergence guarantee implies that the server is to use
> this to advise the client to drop knowledge as needed.
> 
> Please clarify.

If I remember correctly, the entryLeftSet feature was not in the 
original LCUP proposal but was added later due to popular demand. The 
appendix is just out of date. At least I am pretty sure it is. I have a 
vague memory of asking Rich Megginson to remove some of the material 
from that appendix; maybe I missed this one. Note that the entryLeftSet 
BOOLEAN is not optional, so servers must supply a value regardless of 
what sync mode is in use.

-Mark