ietf-nntp Backfill: not again.

[Alan Barrett]

> This sounds like a good start.  My first thought was to approach this
> from the point of view of the slave.  You want to be able to scan the
> newsgroup in question and figure out if there is any new information
> for you to get. (Going through the feed newsgroup by newsgroup was
> an assumption, but from the XREF and XREPLIC talking, I assumed it
> was okay to assume this for the moment.)  If you are the client, the
> easiest thing would be to have a list of all the articles in a given
> group, giving article number and message id.  At that point, you can
> check in your store to see if you have a mismatch, and request further
> information.  The only problem is that if an article is cancelled, we
> do not have any current mechanism to get any cancellation information
> from the master site.

You seem to be thinking of a slave that "pulls" information from the
master (by having the slave talk the client side of a news reading
protocol).  I have been talking about a slave that receives a "push"
feed from the master (by having the slave talk the server side of a news
transfer protocol).  Both types of slaves are possible, but a "push"
feed from master to slave tends to use less resources.

When an article is canceled, the cancel control message is fed from the
master to the slave, so I don't see a problem there.

--apb (Alan Barrett)