There are probably very good performance reasons for calling
qmail-inject directly if you're trying to push out a large amount of
email. For bulk mailings to your tens of thousands of users, for
example. I know at least a few ArsDigita sites had a serious
requirement for that (away.com, probably others), and back in the ACS
3.x days there was serious but incomplete work done on a
high-performance, Qmail specific Bulkmail package.
ns_sendmail is a quite simple Tcl proc, and has a deserved reputation
for slowness. Joel, it does not call the ns_sendmail unix
command, it connects to a port (usually localhost) and does a real
SMTP transfer. Look at the
ns_sendmail code
and see for yourself. SMTP is slow to begin with, and ns_sendmail,
being a low level but quite simple implementation, is much, much
slower than SMTP has to be. It also isn't very featurefull.
Currently,
Mat Kovach
seems to be driving development of an OpenACS replacement for
ns_sendmail, based on Tilmann Singer's acs-mail-lite work. See
e.g. these threads:
Dec. 2002,
Feb. 2003
