Re: Weird glitches for N messages sent to list simultaneously

Tom Lane wrote:
> I've been noticing this for quite awhile: if I commit to all active
> branches, that causes N (currently 6) messages to be sent to
> pgsql-committers at once.  Very often, only N-1 or N-2 of those messages
> come back promptly; the rest are delayed for periods of minutes.
> (It seems like they will come through if someone else posts a message
> to some PG list, though I wouldn't want to swear there is a connection.
> Otherwise it can take quite a few minutes.)
> 
> I noticed this just now with respect to f64340e7436d0f84 et al, and
> thought to look at the mail archives page for pgsql-committers, where
> I see just four messages, same as what came back to me.  So it's not
> just me; there is something odd going on in message submission.
> Anybody care to speculate what?

I looked into the exim logs and all the servers (gemulon the git master,
mahout an intermediate step, magus/makus the SMTP dispatchers) resend
the messages quite promptly -- the 6 messages are in the hands of Malur
(the majordomo2 server) in about 7 seconds total.  Malur accepts the
first 3 messages within 1 second, and the the other three take about 4
seconds total to accept.  From there, malur seems to take its sweet time
to deliver the messages, without any trace to explain the delay.  I
checked the system load munin charts too, and it doesn't appear that
anything goes up the roof after those pgsql-committers postings.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services