Re: ietf-nntp Backfill

[Mark Sidell <[e-mail]>]

> > From: Clive D.W. Feather <[e-mail]>
> > Yet several people at the BOF thought that backfilling was 
reasonable.
>
> I did not hear any server people state that backfilling was reasonable
> behavior.  On the contrary, most server implementors thought this was 
a 
> bug in some implementation.  
>
> I'd like to know exactly what server supports backfilling today.
> If nobody responds, I propose we close this issue and move on.
> We have bigger fish to fry.

When I first implemented Agent, I made what I thought was the 
reasonable assumption that servers didn't backfill.  Then, demon rolled 
out their newsborg server pool (or whatever they call it), which 
apparently does backfill.  My understanding is that the backfilling is 
a side-effect of delays in the propogation of articles amongst the 
newsborg servers.

IAE, we had to deal with the demon servers by adding code to Agent to 
record the ranges of all retrieved articles, and by checking for new 
articles in the gaps.  Using the LISTGROUP command would have made the 
gap checking quicker, but we found that the demon implementation of 
LISTGROUP simply returns a complete list of article numbers in the 
range <min>-<max>, gaps included.  Bummer!

Anyway, as far as I know, demon's is the only server that backfills.  
But, perhaps Clive could provide more information.

Mark Sidell
Chief Programmer
Forte Agent newsreader