Memory Error using Mailman on FreeBSD. How to debug?

Alex Zbyslaw xfb52 at dial.pipex.com
Wed Feb 6 13:57:12 UTC 2008


Lachlan Michael wrote:

>>How big does the mailman process actually get?  top will tell you.
>>    
>>
>
>Mailman values don't budge. None of the mailman processes go over about
>8.5M, which is what they are during idle time.
>  
>

Real puzzler.  I'm surprised not to have at least one process growing, 
though.  Maybe it's not using much CPU and you're not spotting it.

Try running top, then sorting on size (o size inside top) then try your 
mailman email again.  Make sure the top refresh rate is fast enough.  s 
1 inside top would do that, or even s 0 if desperate.

Other things to try:  Up the stack size
    ulimit -s 262144

inside the mailman startup.  Again, I've had processes in the past which 
needed this.

You'd have to check that from a shell (/bin/sh) and first to see that 
your system will allow a bigger value.  If not, I believe that there is 
a sysctl to do that these days but don't have a modern enough system to 
look it up.  A search for MAXSSIZ on google or mail archives may turn it 
up - that's the kernel option but requires a recompile.

Of course, limits may not be the issue at all.  They are a likely 
suspect given your error message, but maybe it's worth checking other 
bits of the mail system.  Can you email a file of the size your are 
trying not through mailman?  Maybe your MTA (sendmail/postfix etc) has a 
limit that somehow causes mailman to get this error.

The final suggestion is to try to trace (ktrace, strace from ports) the 
process that is dying, but I suspect mailman forks a new process to deal 
with the email so how you catch it, I don't know.  Many demons have a 
"run in foreground without forking" option which can be helpful to 
debugging, but I don't know if anything like that is possible in 
mailman.  If you can figure out what mailman actually runs to process 
the email, you could ktrace that from the command line.  Maybe the 
mailman mailing list could give you an incantation to try.

--Alex



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