Subject: Re: LCUP issue: trigger mechanism or not?

From: "Jim Sermersheim" <[email-masked]>
Date: Wed, 04 Sep 2002 21:25:25 -0600

>>> Mark C Smith <[email-masked]> 09/04/02 01:20PM >>>
>Jim Sermersheim wrote:
> >
>> The draft states that it "is intended to allow LDAP clients to
>> synchronize with the content stored by LDAP servers". but also
states
>> that it wants to solve the problem of triggered actions (Section 3,
>> Bullet 3).
>
>I agree that triggered actions should be within LCUP's scope. The LCUP

>authors have tried to balance the server implementation burden with
the 
>client implementation burden. In particular, I would really like to 
>avoid creating an LCUP protocol that requires a server to store 
>client-specific state (that just won't scale when their are thousands
or 
>hundreds of thousands of clients).
>
>
>> Most of the rest of the draft is consistent with the notion of
>> synchronization, but tends to downplay support for triggered
responses.
>> Do we want this to be a useful event driver, or is the idea that we
just
>> preserve the easy stuff of what prior drafts could do?
>> 
>> Specifically, the left-out items in Sections 5.1, 5.2, and 5.3
deter
>> from the effectiveness of the "persist" mode.
>> 
>> Current users of Persistent Search rely on the notion of change
types.
>> Section 5.2 assumes that change types are used for partial
replication,
>> and thus discounts them as useful for LCUP. I don't think this is
>> valid.
>
>Are you saying that LCUP should support clients that only want to
store 
>  a subset of the entries that are targetted by the LCUP search they 
>issue? 

No, even worse. I'm saying there are clients that wish to store
nothing. They only want to be triggered when a certain action occurs.

>Even if you do want to support that, I don't see the problem. The 
>LCUP model (as defined today) is that it is up to the client to 
>determine whether a change is interesting or not. The assumption is
that 
>clients will store UUIDs for each entry they are interested in, and
that 
>the client can compare stored data with the new entry data to
determine 
>what has changed. That does not seem like an excessive burden to me.

For a client that stores nothing, and makes no comparisons today with
psearch, the extra burden is huge.

>A related comment: perhaps section 5 should be moved to an appendix
that 
>is named "Features Left Out of LCUP." It is not core to LCUP, but is 
>useful to provide historical context and rationale for why some things

>are not included in LCUP.
>
>-Mark Smith
>  Netscape

Jim