[Mailman-Developers] Requirements for a new archiver

[J C Lawrence]

On Wed, 29 Oct 2003 16:29:09 +0100 
Brad Knowles <brad.knowles at skynet.be> wrote:
> At 12:41 AM -0500 2003/10/28, J C Lawrence wrote:

>> Quite, this is how/why NNTP uses Message-IDs are unique indexing
>> qualifiers.

> Problem is that client-assigned message-ids are not guaranteed
> unique.  

Right, and that was the point.  If we do nothing to Message IDs we don't
change external behaviour.  If we use a netnews backing store for the
archives and we don't dick with the message IDs we run the risk of some
messages never reaching the archives.  If we use a netnews backing store
and dick with message IDs we can offer various levels of guarantee that
messages reach the archives, and of pissing off users because we messed
with the Message IDs.

As always, you get to pick.

> Everything else could quite feasibly collide, and you'd wind up with
> multiple non-unique message-ids.

In which case the many people currently using ID-based dupe collapsing
(eg default Exchange config) will lose messages, and the archives will
lose messages....OR...we offer some level of guarantee (see yesterday's
discussion) with the matching trade-offs.

> You need a guaranteed unique id to be used as a primary index field.

"Need" is a strong word.  Its very deployment and use-case sensitive.
There are a large number of cases where I'm content to rest on the
assurance that the Message IDs arriving at my lists will always be
unique.  There are also a large number of cases where I'm not willing to
make that assessment, as well as a large number of cases where I'm
willing to simply discard anu duplicated Message ID messages at the
archiver level.  Similarly, there are cases where re-writing the Message
IDs in any form is significantly troubling, and cases where its not.

"Need"?  No.  It is a deployment choice with easily understood
ramifications.

-- 
J C Lawrence                
---------(*)                Satan, oscillate my metallic sonatas. 
claw at kanga.nu               He lived as a devil, eh?		  
http://www.kanga.nu/~claw/  Evil is a name of a foeman, as I live.