[Mailman-Users] Efficient handling of cross-posting

Brad Knowles brad at shub-internet.org
Tue Jan 29 01:59:07 CET 2008

On 1/28/08, Mikhail T. wrote:

>  Yes, of course. But a single mailman installation hosting multiple mailing
>  lists already has the complete knowledge, does not it?

Nope.  All you have for each list knows is a bunch of e-mail 
addresses that are subscribed.  When sending out a message that has 
been cross-posted to multiple lists, one thing you could do is an 
equivalent to "sort | uniq" for all of the recipient e-mail 
addresses, but you have no way of know if a single person has 
multiple different addresses that are subscribed to one or more lists.

And I believe that interactive mail messages are handled separately 
from digests.

>  Yes, absolutely -- the only key is Message-Id. Even if a hash of the message
>  body /could/ be used as the key, I think, a different Message-Id means, the
>  message should be sent again.

Message-id is not really good enough.  There have been many examples 
of clients that do not create sufficiently unique message-ids for 
different messages.

But if the recipient wants to that that risk within their mail 
system, that's their choice.

>  I think, this function is already here. When I first sent message to this
>  list, it bounced, because I was not a subscriber. The bounce suggested, that
>  I subscribe ALL of my addresses and mark some of them as "NOMAIL". This would
>  seem to indicate, that multiple addresses-per-person feature is already
>  established.

Uh, no.  I think I may have written that bounce message.  I guarantee 
you that this feature does not yet exist in Mailman.

>  This is true. But if /most/ duplicates are eliminated by this, then the
>  remaining /few/ may be acceptable to allow cross-posting to relevant mailing
>  lists.

Most of the anti-duplication features can't be delivered until 
Mailman3.  The sister-list concept that Mark has introduced with 
Mailman 2.1.10 is the best we're likely to be able to see for a long 

>  AFAIU, the message will appear in the search results multiple times -- once
>  per mailing list. That is not justified -- the results should contain no
>  repetitions...

Mailman does not incorporate any search function, therefore which 
searches return which messages is totally and completely irrelevant 
to Mailman.

Moreover, searches across multiple lists should most definitely 
return multiple hits for the same message, if it was posted to 
multiple lists.  If you want any other kind of behaviour, then that 
would be up to you and how you configure your particular search query.

No search engine author in their right mind should ever consider 
doing de-duplication on their own, although they might be willing to 
provide that feature to customers who demand the option.

Brad Knowles <brad at shub-internet.org>
LinkedIn Profile: <http://tinyurl.com/y8kpxu>

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