Re: broken newsserver seeming to give more
clemens fischer schrieb am Sunday, den 02. February 2003:
> Matthias Andree <ma@...>:
> > This pretty much looks like a problem in the communication between your
> > fetchnews and the upstream -- and because leafnode doesn't catch
> > SIGPIPE, it aborts, and as a consequence, the water marks (actually a
> > misnomer, they are rather levels) are stale, a stale lock file is lying
> > around and all that.
> btw, i never really understood the waterlevels. could somebody
> please explain what they mean?
OK, news readers have two means to access an article:
1. by message-id (uncommon for newsreaders except for the "lookup by
message-id" function and maybe for references that cannot be
satisfied in the currently displayed newsgroup)
2. by GROUP and ARTICLE commands, where the ARTICLE commands take
numbers that are server- and group-specific -- and also deposited in
the Xref: header that isn't propagated between servers.
It is assumed by newsreaders that the article numbers are strictly
monotonically increasing, and therefore, leafnode stores them in the
groupinfo file. The levels (low/high) note the lowest (less critical)
and highest (critical) article number available on the server, where the
highest number must not be lowered even if articles with high numbers
expire or are cancelled (only leafnode-2 actually executes cancels,
leafnode-1 just transports them as regular postings).