[ILUG] Programmatic mail sending with Postfix

[Philip Reynolds]

Niall O Broin <niall at linux.ie> 34 lines of wisdom included:
> >No, unfortuantely it's not faster than using SMTP connections due to
> >the way the mails are processed. 
> 
> Hmm - I find that curious - because with an SMTP connection eventually a file
> has to be created in the maildrop directory. And I'd have thought that running
> postdrop would be a little faster than an SMTP connection. But that's only a
> gut feeling.

smtpd doesn't use the maildrop queue directory at all.
Mails via ``sendmail(1)'' go:

	sendmail -> maildrop -> pickup -> cleanup

Mails via SMTP (and hence smtpd) go:

	smtpd -> cleanup

You can use QMQP, but from what I've seen, I dislike it. It's one
message per transaction (IIRC) and like ESMTP pipelining the only
real benefit comes when you have multiple recipients for the same
mail (i.e. unique messages aren't great).

It's trivial to communicate with a QMQP server once you read DJB's
text and work in netstrings functionality. However, I believe ESMTP
pipelining works just as well for large volumes of mail and has
added advantages in some scenarios (which won't apply to most local
bulk processing of mail for remote destinations).

If your messages aren't unique, and you literally have one message
to send to a couple of thousand recipients there should be a
negligible overhead in using QMQP/ESMTP pipelining.

-- 
Philip Reynolds                      | RFC Networks Ltd.
philip.reynolds at rfc-networks.ie      | +353 (0)1 8832063
http://people.rfc-networks.ie/~phil/ | www.rfc-networks.ie