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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!uunet!in2.uu.net!128.248.178.247!koobera.math.uic.edu!djb From: djb@koobera.math.uic.edu (D. J. Bernstein) Message-ID: <1996Dec2302.43.17.4992@koobera.math.uic.edu> Date: 23 Dec 1996 02:43:17 GMT Newsgroups: comp.mail.sendmail,comp.mail.smail,comp.unix.bsd.freebsd.misc Subject: Re: Sendmail vs. Smail... References: <57tf61$gq7@raven.eva.net> <59bjh9$fl1@ezekiel.eunet.ie> <1996Dec2000.07.45.5990@koobera.math.uic.edu> <slrn5brnga.4fs.jon@black.oaktree.co.uk> Organization: IR Lines: 36 Xref: euryale.cc.adfa.oz.au comp.mail.sendmail:35445 comp.mail.smail:2753 comp.unix.bsd.freebsd.misc:32872 Jon Ribbens <jon@oaktree.co.uk> wrote: > D. J. Bernstein <djb@koobera.math.uic.edu> wrote: > > False. Measurements have shown at three separate sites that switching > > from sendmail to qmail _reduces_ traffic. > But that's not what he said, is it? He said ``considerably more.'' That's false. The change is so small that it's wiped out by other (minor) differences. > This discussion is about grouping RCPTs versus not grouping them, Actually, it's about sendmail vs. smail. It expanded to talk about Zmailer, Exim, and qmail. Notice that these are all _real_ MTAs. Vaporware MTAs might be fun to fantasize about, but they won't deliver your mail. > Presumably you would therefore agree that RCPT grouping > is much preferable if ESMTP pipelining is available? PIPELINING certainly improves the average case (though in extreme cases there's still a slight serialization penalty). Unfortunately, it's not widely supported. > a dynamic system which tried to guess how many RCPTs > should be grouped in a single transaction before the > grouping becomes detrimental would be better than either > never grouping or always grouping? Not necessarily. The cost of collecting data to guess more effectively may swamp the (insignificant) benefits. I suggested this to DRUMS back in March, and I'd like to try it out someday if they don't prohibit it, but without profiling I can't be sure whether it'll be beneficial. ---Dan Put an end to unauthorized mail relaying. http://pobox.com/~djb/qmail.html