On Mon, 10 Sep 2001, Matthias Andree wrote:
> On Sun, 09 Sep 2001, Pavel Kankovsky wrote:
>
> > How huge is ``huge''? Ten times faster? 5 percent faster?
>
> Depends on the client. qmail-remote does not use PIPELINING even if the
> other side offers ist.
Indeed. But I want to see numbers. Profile, don't speculate! ;)
> > How is the difference affected by the size of messages?
>
> Not at all.
Difference per one message is not affected. Difference per one byte of
data is affected: there are less roundtrips in SMTP when you send one
1MB-message than when you send 100 10kB-messages. QMQP would save some
roundtrips too but less than SMTP, ergo the difference would become
smaller for bigger messages.
> > How is the difference affected by SMTP pipelining?
>
> Approximately the same. SMTP PIPELINING and QMQP get closer to each
> other the more recipients the mail has.
Approximately the same == not at all? If the answer to the previous
question was not ``not at all'', it would make some sense.
> > How is the difference affected when multiple concurrent connections are
> > used (amortizing RTT-induced delays in SMTP)?
>
> Small, that's why qmail spawns multiple qmail-remote clients if it has
> more than one mail to send.
Excuse me? Do you want the say ``the difference would be small'' or ``the
difference would not be affected much''? (I suppose you meant the latter.)
> Neither example counts RTTs for the mail body or for huge mail
> envelopes, which can occur if the window is too small because you have
> real-high-latency links or high bandwidth.
Anyway, both SMTP (with PIPELINING) and QMQP would probably suffer in a
less or more equivalent way in this case.
> > How many people using ``a typical modem link'' send enough email to
> > feel that ``huge difference''?
>
> Personally, my mails have up to 10 recipients, more only in exceptional
> cases, uusually only 1 recipient.
I do not send many multi-recipient mail (esp. across a modem link) either.
But it does not matter. You yourself showed (E)SMTP + PIPELINING can be as
fast or even faster than serialized QMQP (yes, serialized: it is not a
good idea to run too many paralel connections through a slow modem link,
is it?) when the number of messages is something like 4 or 5 or higher. On
the other hand, the for a smaller number of messages, the differences
would be too small, measured in seconds in the worst case. So, where is
the *huge* benefit of QMQP?
--Pavel Kankovsky aka Peak [ Boycott Microsoft--http://www.vcnet.com/bms ]
"Resistance is futile. Open your source code and prepare for assimilation."
