Subject: Re: Abysmal Mailing List Performance
To: Gary D. Duzan <>
From: Perry E. Metzger <>
List: current-users
Date: 07/02/1996 14:13:40
"Gary D. Duzan" writes:
>    Has anyone else noticed that it takes forever for messages posted to
> the NetBSD lists takes forever to get out? It isn't unusual for me to
> see messages posted three or four days after they were written, including
> my own. Are there any plans to improve the list performance?

The problem, simply stated, is that all email on the NetBSD machines
gets queued before sending, and that the machine is slow and the
queues get huge. Most machines end up with a separate sendmail process
for every message going through and only queue stuff that can't be
delivered instantly, but the NetBSD mail machine is rather weak and
can't handle the load that imposes.

The core of the problem is that sendmail is essentially single
threaded -- every network delay on every round trip on every piece of
mail going out of the queue ends up delaying the entire mail
queue. Delivering mail should not have to be slow or CPU intensive on
any machine, even a slow one. I have as a pet project to replace
sendmail's delivery mechanism with an event driven one that can
deliver to many machines in parallel without imposing load on a
machine -- one of my guys is writing the event driven library right
now for another project, in fact. If this ever gets off the ground,
I'll donate the code.