article propagation delay
Pavel V. Knyazev
pasha at surnet.ru
Wed Mar 13 15:12:15 UTC 2002
> If you figure typical article reception rates of ~15 articles/second,
> 125 outstanding checks could be an order of 10 second check window...
What time it usually tooks to the small article to be offered and
transmitted to another site? Consider the sites are working on a
fat fast line with ~50 ms RTT.
> Another possibility might be the scenario whereby a site checks, but
> while it is waiting for the response, the article gets "cancelled out from
> under it" (so to speak). I don't think articles with pending checks are
> locked to prevent cancellation...
We may refuse all cancels as a workaround.
Howver, they may not ask if we want to receive this cancel :-)
> Likewise, consider a situation where a backlogging peer consistently
> overflow their permitted backlog... If a feeder has a small buffer for a
> downstream feed, I could also see that resulting in scenarios where
> articles aren't available following a successful check...
As my point of view, a good site won't even offer an article
if backlogging occurs. Otherwise it will send a lot of duplicates.
> >It might be nice to have an option in incoming.conf to disallow a
> >incoming peer from being able to put an entry in the precommit cache.
> That would be cool, indeed. Likewise, something to limit the number of
> outstanding checks per particular incoming peer.
How could we ask INN developers to realize all these new features?
> >might also be nice to have some statistic collection on the precommit
> >to see the percentage of precommit wins per peer and the average delay
> >the check and the complete reception of the article (per peer).
> And to add to the wish list, I'd love instrumentation on incoming peer
> treatment of "defers" (for example, innfeed has the option to
> articles) -- I'd love to know which sites appear to be doing that (e.g.,
> which incoming sites *never* retry after getting a defer).
> Flip side of that would be the ability for the receiving peer to control
> which incoming peers are handed defers rather than refusals -- there may
> some sites that you want to tell "don't bother retrying".
That's very easy to check if a site does retransmit retries.
First, you need to turn-on deferral responces.
seconds: 59956 duplicates: 8553 ip address: 126.96.36.199
offered: 192644 uw newsgroups: 55 active cxns: 5
accepted: 2885 uw distributions: 548 sleeping cxns: 0
refused: 277690 unapproved: 0 want streaming: Yes
rejected: 13898 filtered: 0 is streaming: Yes
size: 6.2Mb bad sites: 0 duplicate size: 14.4Mb
Ihave: 0 SendIt: 0 Got: 0 Deferred: 0
Check: 294519 SendIt: 16783 Got: 157356 Deferred:
Takethis: 16783 Ok: 2885 Error: 0
Cancelrejects: Ihave: 0 Check: 18506
(consider clara does not resend deferred messgaes)
We see that inn reports that there were 192644 articles offered,
however there 294519 checks were made (and 101828 articles
were deferred). Just calculate 192644 plus 101828 ...
When a particular site DOES retransmit articles you'll see
that the difference between "checks" and "offered" will be
much less that the number of deferred articles as inn reports.
ps. this is a real run-time statistic ...
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