Re: [Exim] 1000 bcc email slow - why?

On Thursday, October 4, 2001, at 11:19 AM, Dave C. wrote:
> Uhm.. My guess would be that its doing the DNS lookups so that it can
> figure out what host(s) to send the message to. Unfortunately, you
> really can't skip that step. As for why its taking 30 minutes, perhaps
> some of the DNS servers for some of the domains he is trying to send to
> are responding very slowly or not at all (resulting in it having to wait
> for them to time-out)

Feel free to correct me if I am wrong. What appears to be happening is
that Exim must finish the _entire_ DNS lookup phase (including all
recipients) before it delivers a single piece of mail. If instead you
write a program to take the message and duplicate it replacing the
recipient list with only a single recipient on each message, you will
get much better performance. Why? Because one exim process does the DNS
lookups serially. (I think). The other way you will have several
hundred processes deliverying a few messages each. You won't utilize
batched devliery as much, but the mail will get to its destination much
faster -- and that is point, no?

We can deliver around 100 message/second this way on commodity hardware.

--
Theo Schlossnagle
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