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Re: [Pan-users] "missing" articles
From: |
Duncan |
Subject: |
Re: [Pan-users] "missing" articles |
Date: |
Tue, 18 Mar 2003 10:18:20 -0700 |
User-agent: |
KMail/1.5 |
On Tue 18 Mar 2003 04:54, Alberto BARSELLA posted as excerpted below:
> This is perfectly normal when the articles have not entirely propagated
> to a newsserver: usually it's enough to look one day later and everything
> is there. Still, for this episode even after 2-3 days the situation was
> exactly the same.
>
> Now, if instead of opening the group and downloading new headers, I force a
> reload of all headers (using "more download options..."). The "missing"
> articles appear (and they appear marked as "read").
> Could this be a problem with article counting? My knowledge of NNTP is
> low, and I don't know exactly how wraparound in article counting is handled
> in large-volume newsgroups.
This isn't likely to be wrap-around. More likely, it's due to the way the
server is handling it's articles, back-filling the numbering, which can mix
up some readers, including PAN.
It works like this. Each server has a message count for each individual
newsgroup. Say you log on today, and a particular group has message numbers
from 10200 to 11350. You read what you want, mark the rest read, and quit.
Tommorrow you go back and check for new messages. PAN looks and sees that
the last message that was there yesterday was 11350, so it tells the server
it wants any messages between that, and the new max count, say 11520.
So far so good. However, take for example my ISP, Cox, which has three news
servers. To keep them syncronized, the numbers are assigned at a central
location, so if one server goes down, we can switch to one of the others
without having to d/l all headers again, since the numbers are all
syncronized on all three servers.
Now, consider what happens when one server gets behind. The main feed
continues to get new articles in, and number them, but the troubled server
only gets a few of those, and there are gaps in its numbering. If the user
now marks all messages as read, and the user agent (PAN, in this case)
interpretes that as all messages up to (in the above example) 11350, but
11237 and 10976 come in later, the user agent will wrongly think those are
already read, and not display them the next day.
I might be wrong about this, as I haven't looked at the PAN innards to see,
but I think PAN normally tracks numbering individually, so this problem
shouldn't occur. However, it's possible that when you mark an entire group
read, rather than marking the individual articles read (select all, mark as
read), it uses the highest article number seen to track that, and this may
cause the issue you saw. Thus, I'd suggest only marking the individual
articles as read, probably using select all, mark as read, as I mentioned,
rather than mark group as read. Hopefully, that cures the problem.
Of course, occasionally, usually when the server itself has problems, it may
reset its article numbering, and EVERYTHING would get screwed up. The same
may occur if you switch servers by simply changing the address of the server
in PAN, and the servers aren't number-syncronized. In these instances,
resetting the group, or d/ling all headers, may be necessary, to get things
back on track. However, from your description, that shouldn't have been
necessary, except that you'd apparently marked the entire group read, rather
than individual articles, so that's what you ended up doing, necessary or
not.
Of course, there may be other occasional instabilities or bugs, that cause
one-off problems. However, it shouldn't occur on a regular basis. If it
does, there's something else wrong.
--
Duncan
"They that can give up essential liberty to obtain a little
temporary safety, deserve neither liberty nor safety." --
Benjamin Franklin
- [Pan-users] "missing" articles, Alberto BARSELLA, 2003/03/18
- Re: [Pan-users] "missing" articles,
Duncan <=
- Re: [Pan-users] "missing" articles, Alberto BARSELLA, 2003/03/18
- Re: [Pan-users] "missing" articles, Duncan, 2003/03/18
- Re: [Pan-users] "missing" articles, Duncan, 2003/03/18
- Re: [Pan-users] "missing" articles, Brian Morrison, 2003/03/18
- Re: [Pan-users] "missing" articles, Duncan, 2003/03/19
- Re: [Pan-users] "missing" articles, J.B. Moreno, 2003/03/19
- Re: [Pan-users] "missing" articles, Brian Morrison, 2003/03/20