[Mailman-Users] Mailman 2.1.6 slowness...?

Brad Knowles brad at stop.mail-abuse.org
Sat Jul 16 21:58:04 CEST 2005

At 11:16 AM -0400 2005-07-16, Jeff Squyres wrote:

>                                 Specifically, mails to @example.com may
>  not be conveniently lumped into 1 or 2 transfers to the MTA -- in a
>  worst case, they may be spread out across 1000/SMTP_MAX_RCPTS transfers
>  to the MTA.

	I'd have to check the code, but I'm pretty sure that Mailman will 
sort the recipient list, which will allow the MTA to optimize 
delivery to each domain -- at least, within the parameters of the 
VERP and "personalization" settings.  However, it will only break 
that list up at the boundaries specified by SMTP_MAX_RCPTS.

>  We checked into that, and seem to have a pretty reliable DNS connection
>  (and its cached locally).

	Some nameserver caching systems occasionally have problems. 
Check with your DNS server administrators to make sure that they 
haven't been having any such problems.  We've seen a lot of 
complaints lately on comp.protocols.dns.bind, but maybe that's just a 
seasonal thing or something.

>  I don't think we're a victim of tarpit kinds of remote MTAs, but even
>  if we are, lowering the SMTP_MAX_RCPTS should help with that, right?

	It might help.

>  That is, if a recipient has a slow MTA, then *essentially* only the
>  other (SMTP_MAX_RCPTS-1) other recipients will be penalized (because
>  the others will be occurring in more-or-less parallel).  Is that right?

	If the deliveries to the other recipients are not tar-pitted, 
then you would definitely see an improvement, yes.  That's one of the 
advantages of higher parallelism -- up until the point where every 
recipient gets their own unique copy of the message (which would 
happen if you turned on VERP and "personalization" for each and every 
list), you have fewer and fewer other recipients who might 
potentially be slowed down by the message currently being delivered 
to a slow site.

Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.

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