[Mailman-Developers] Huge lists

J C Lawrence claw@kanga.nu
Wed, 24 May 2000 07:32:35 -0700

On Wed, 24 May 2000 09:51:29 +0100 
Nigel Metheringham <Nigel.Metheringham@VData.co.uk> wrote:

> Remember that unless the sender side is using qmail or VERP then 2
> million addresses all in this domain would normally optomise down
> to a single SMTP message transaction with 2 million RCPT TO's.

Actually on the input side it would be 2M/SMTP_MAX_RCPTS where
SMTP_MAX_RCPTS defaults to 500.  Additionally, Exim (I haven't
checked Postfix, but I doubt it) does not collapse identical spool
entries with different RCPT TO lists, so you're still left with the
same number (checking for identicallity is expensive).

> You may also find that you get an unexpected speed up at the
> inject end since the domain name may (certainly should) be cached
> in the MTA and/or local dns server/cache and so if the MTA does
> verification/routing during SMTP receipt the first address would
> prime the config and all the others would shoot through very
> quickly.

True.  However for anybody running such a large mailing list, I
would expect them to have configured their MTA to not attempt
pre-lookups for messages arriving from MailMan.  Certainly that's
how I've configured mine.

J C Lawrence                                 Home: claw@kanga.nu
----------(*)                              Other: coder@kanga.nu
--=| A man is as sane as he is dangerous to his environment |=--