ietf-nntp Wildmats (was: draft posted)

[Clive D.W. Feather]

Russ Allbery said:
> Clive Feather agreed with this in <20001116120658.N47729 at demon.net> of
> 2000-11-16:
> 
>     The unordered bit is in there, but it has:
>     
>       Each message-id SHALL appear only once in a response.
>     
>     I'd agree with you that it should be changed to:
>     
>     ! A message-id MAY appear more than once in a response.
> 
> As near as I can tell, there was no further discussion.  RFC 977 is silent
> on this point.  Does anyone remember why this was changed in our current
> draft (relative to RFC 977)?

I don't know who first put the point into our draft, but they clearly
didn't have the necessary experience with servers. I think we need words in
there, but they MUST be the "MAY appear more than once" words.

>> Does any harm actually arise if it is repeated? The worst that can
>> happen is that the (sucking) client fails to notice that it has already
>> asked for this article once before, asks for it again, and then finds it
>> doesn't need it after all. A little inefficient, perhaps, but nothing
>> actually breaks.
> 
> This analysis seems correct to me.  Clients that really care could always
> eliminate the duplicates themselves, and in general it's better to push
> straightforward work like onto the client rather than the server since the
> server is likely to have a higher load.

Furthermore, the server may be generating the list in several parts (e.g.
by scanning each newsgroup in turn) and may not have any convenient way to
spot the duplicate.

Meanwhile the client has to be prepared for duplicates whenever it fetches
with an overlapping timestamp.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:  +44 20 8371 1138
Internet Expert     | Home:  <clive at davros.org>  | Fax:  +44 20 8371 4037
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