[NNTP] Article Reinstatement

[Julien ÉLIE]

Hi Sabahattin,

> If a client should not be aware that an article has been removed
> pending reinstatement, it has no reason to suspect that the low
> watermark will ever decrease.

The low watermark can not decrease.



> Example: news.test has 5 messages, min=1 max=5.  Article 1 is
> removed.  Server indicates on group entry to news.test, min=2 max=5
> no=4.  The client updates its counters to indicate that article 5 was
> the last article seen.  Article 1 is replaced.  Client connects,
> server indicates min=1 max=5 no=5.  How is the client to ensure the
> retrieval of article 1?

It is not an RFC-compliant behaviour.
min could not have been set to 2.

RFC 3977, Section 6.1.1.2:

    o  Articles may be reinstated in the group with the same article
       number, but those articles MUST have numbers no less than the
       reported low water mark (note that this is a reinstatement of the
       previous article, not a new article reusing the number).

[...]
    No similar
    assumption can be made about the high water mark, as this can
    decrease if an article is removed and then increase again if it is
    reinstated or if new articles arrive.



> The low watermark may certainly indicate its
> presence, but it can hardly assume that an article was reinstated
> simply because on this occasion min=1 is the smallest value seen; the
> article numbered 1 may already have been fetched under normal
> conditions, or the heuristic will not work at all if group expiration
> on criteria other than number of articles has occurred, for
> instance.
>
> Does anybody have any ideas?

I do not understand your point.

Wouldn't it rather be:

news.test has 5 messages, min=1 max=5 count=5
1. remove #1
min=1 max=5 count=4
2. reinstate #1 and remove #3
min=1 max=5 count=4

So a client that comes between action 1 and action 2 will never see #1; 
it won't ask for #1 afterwards because the high water mark is 5.  The 
same way as a client coming after action 2 will never see #3.
But is it really a problem?

-- 
Julien ÉLIE

« Il faut que j'en parle à notre chef ; ce n'est pas normal que des
   Romains bravent les dangers de la forêt, surtout quand les dangers,
   c'est nous ! » (Astérix)