[Mimedefang] "No free slaves" vs. "Queueing request"

[David F. Skoll]

On Thu, 22 Jan 2004, Andrzej Marecki wrote:

> Why are there *much more* messages of this kind:
> mfconnect: No free slaves
> ... than messages like this:
> All slaves are busy: Queueing request (xx queued)
> ... in my syslog?

Because of the way queuing works.

When a *new* SMTP session is opened, if there are no free slaves, the
session is tempfailed and no queueing is done.

If an *existing* SMTP session tries to do work that needs a slave, then
the request is queued (if possible).  The idea is that existing SMTP
sessions should get priority (because you've already expended resources
on them.)  So we try hard to complete existing sessions, while making
new ones retry.

Regards,

David.