Klarinet Archive - Posting 000065.txt from 1998/09

From: Larry Paikin <larrypaikin@-----.net>
Subj: Re: [kl] Off-list Computer Question
Date: Wed, 2 Sep 1998 21:26:05 -0400

Oh...

Mark Charette wrote:

> From: SDSCHWAEG@-----.com>
> >Hey, Mark -
> > Why do I sometimes get "reply" posts BEFORE I receive the one that
> asks
> >the question? Just curious...
>
> The mail software on sneezy is qmail, and the mailing list software is
> ezmlm. The interaction is:
>
> qmail is set up to have 30 mail queues (just enough to ordinarily
> saturate sneezy's Internet link)
>
> ezmlm is currently handling about 600 people on this mailing list.
>
> When a message comes in ezmlm will hand off about 20 addresses/mail
> queue, however, there may already be messages in any queue waiting to go
> out.
>
> Each mail queue takes its list of addresses, and one at a time, tries to
> connect with the recipient mail host. If the connection succeeds, the
> message is sent over and the next address gets to the front of the
> queue. However, sometimes the recipient machine is off-line or the
> Internet is slow. In that case the mail queue will try for a minute or
> so before moving the address to the end of the queue and trying the next
> address. So ... some queues move messages out faster than others.
>
> If another message comes in while the mail queues are busy, the
> addresses get distributed to the least-filled queues first. So ...
> sometimes you'll get the answer before the question - the queue the
> first message was in is stalled for a few moments (and hasn't gotten to
> your address yet), but someone else has already read the message and
> answered. Your address was in another queue for the reply, and got sent
> out sooner.
>
> A little picture:
>
> 1) Message 1 comes in, and starts getting sent out :
> Queue 1 - a@-----.com(msg1)
> Queue 2 - d@-----.com(msg1)
>
> 2) Queue 1 stalls because bar.com is off-line, but we check for a minute
> or so. Queue 2 sent all its messages already. a@-----.com hasn't been sent
> yet.
> Queue 1 - a@-----.com(msg1)
> Queue 2 - <empty>
>
> 3) A response (message 2) comes in ... Queue 2 gets filled 1st, since
> it's empty.
>
> Queue 1 - e@-----.com(msg1)
> b@-----.com(msg1)
> Queue 2 - a@-----.com(msg2)
> d@-----.com(msg2)
>
> 4 b@-----.
> Queue 2 is all done by now.
>
> Queue 1 - b@-----.com(msg2)
> a@-----.com(msg1)
> Queue 2 - <empty>
>
> 5) As you can see, a@-----.
>
> Probably a longer explanation than you figured you'd get :^)
> ----
> Mark Charette@-----.org
> Webmaster, http://www.sneezy.org/clarinet
> All-around good guy and devil-may-care flying fool.
> "There can be no freedom without discipline." - Nadia Boulanger
>
> -------------------------------------------------------------------------

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