Re: [exim] connection_max_messages vs. batch_max

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Author: Nigel Metheringham
Date:  
To: jeffrey.starin
CC: Exim-Users Mailing List
Subject: Re: [exim] connection_max_messages vs. batch_max
[Please do not take mailing list threads private - it means when someone
with the same question follows the thread it just stops partway. Also I
answer mailing list stuff (including that copying me directly) pretty
much on a whim, so only sending to me rather than the list risks the
thread stopping because I don't feel like answering this one...
Exim-users list copied back in...]

Jeffrey Starin wrote:

> I know it's the correct file because when I attempt to change or input
> the value and then restart, I receive errors. My ISP is telling me that
> these values are "private" -- I've never heard of such a setup.


I suspect they are making things up there.

> Anyway, my ultimate goal is to have all my messages destined, for say,
> Yahoo, go in one connection rather than several connections, and I wish
> to control that value. Is it the connection_max_messages I need to set
> or the batch_max I need to set?


Many distinct messages, then you want to set connection_max_messages to
something higher. However because exim does not run as a centrally
controlled setup, you may still find that messages are independently
routed and sent down different SMTP sessions even to the same
destination. The way to mostly avoid this is to use queue_smtp_domains
to select the domains you wish to to have queued and then batch
delivered when a queue run happens. This does, of course, affect
latency of the system.

The batch_max and connection_max_messages are transport options, so are
added to a transport, giving you something like this

    remote_smtp:
      driver = smtp
      connection_max_messages = 30


Remember the other end in an SMTP transaction is quite at liberty to
decide it wants no more than n messages in a single connection, or have
other limits on the numbers of recipients.


    Nigel.


-- 
[ Nigel Metheringham ------------------------------ nigel@??? ]
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