Message-Id: <199603060903.EAA03504@wilma.cs.utk.edu>
From: Keith Moore <moore@cs.utk.edu>
To: djb@koobera.math.uic.edu (D. J. Bernstein)
cc: drums@cs.utk.edu, moore@cs.utk.edu
Subject: Re: re PIPELINING 
In-reply-to: Your message of "06 Mar 1996 07:31:59 GMT."
             <19960306073159.13521.qmail@koobera.math.uic.edu> 
Date: Wed, 06 Mar 1996 04:03:26 -0500
Sender: moore@cs.utk.edu

> If you go through your logs you will find that the _maximum possible_
> benefit of multiple RCPTs for your host is under 1% of your CPU time,
> under 1% of your processes, under 1% of your network bandwidth, and
> under 1% of your storage, compared to your normal resource use for mail.

My experience contradicts this.  We run a mailing list with
5000 recipients.  It used to send each message in a separate envelope
and took an average of eight hours to attempt delivery to each
recipient.  I rewrote it to put all the recipients in the same
envelope and it took twenty-four hours or more -- the time was 
highly variable due to the variance in the number of unreachable
hosts for which the connection had to time out before the MTA
would go to the next recipient.  I then rewrote the code again
to parallize delivery, but to put up to twenty different domains
in an envelope.  Now it takes an average of two hours to attempt
delivery to each recipient.

Incidentally, the original motivation for my rewriting the list
code was that it tended to fill up the available disk space
with queue files (~140k each) for each of the recipients.

So my experience is that multiple RCPTs in an envelope can save both
disk space and latency over one RCPT per envelope.

--------
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