Re: does filtering increase modem traffic?

On 09-May-2003 Dan Jacobson wrote:
> Gentlemen, in noffle.conf I have chosen to do
> filter bytes>19k action=discard
> filter group=gmane.spam.detected action=discard
> 
> I am worried that now that I have chosen filtering, what once was just
> a simple download now needs to have also a preliminary header check
> for each article.

Filter rules that require knowing the newsgroup name - those that specify a
group or number of crossposts - do require fetching extra information, to whit
the contents of the Newsgroups: header for each message. This is done with a
XHDR request to upstream before the overview information is obtained. All the
other rules work on the standard overview information that Noffle downloads all
the time, so don't add any overhead.

So, in the above example, the first rule has no overhead, the second rule does
have an overhead.

> Me adding those two lines will now cause the bytes going over my
> modem to increase by how much?  These days headers are bigger than
> many bodies anyway...

The increase in data will be downloading just the Newsgroups: lines for each
article.

> Is all the filtering accomplished in a overview phase that we have to
> do for the particular group anyway, thus merely using the CPU more,
> not the modem?  Or do we laboriously get each message's header first?
> 
> Am I wasting just CPU or also phone money filtering for
> gmane.spam.detected even for other servers than gmane?

Phone money, unfortunately. At the moment there is no way to switch off a
filter on a per-server basis.

-- 
Jim Hague - [email protected]          Never trust a computer you can't lift.


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