The mailing list for listmasters using Sympa

[Olivier Salaün - CRU <address@concealed>]

Hi Adam,

Adam Bernstein wrote:

> We're currently trying to nail down a bug that recently began causing 
> our sympa.pl process to quietly stop processing anything until it's 
> restarted.  Before I file a bug report, I'm trying to understand 
> better what's happening, and we have a few clues but not the whole 
> picture.
>
> One question that will help me figure it out is:  When a digest is 
> sent to a list, is sympa.pl supposed to fork a new process?  When our 
> system stops working, we're seeing extra sympa.pl processes running, 
> started at the time that the digest was sent to a certain list.  I'm 
> wondering if the process shouldn't have started at all or if it should 
> have started and then terminated.  We're currently running Sympa 5.1.2 
> with the default process profile, ie. one process for both commands 
> and messages.

No fork is performed specifically for digest, but the process forks when 
it is sends an email. The only goal for the fork is to launch a sendmail 
process via exec().

> To describe the problem somewhat more fully:  There seems to be a 
> problem related to sending digests, usually (but not always) on one 
> particular list, which leaves one or two extra sympa.pl processes 
> running, although the digest is sent to all the proper subscribers and 
> the "Digest sent" message is logged.  The system then continues 
> working properly, processing commands and messages, until some point 
> hours later when sympa.pl stops processing anything.  We then 
> sometimes find a mhonarc process running and hung, with no 
> corresponding "Archiving..." log entry (which is weird because that 
> logging should happen before the call to mail2arc in archived.pl), or 
> else we find that the last logged action was a moderator giving the 
> "distribute" command on a moderated list, which does not get processed 
> until after a process restart.  We kill everything and restart sympa, 
> and then all is well.

The mhonarc process you see might the one run via 
List::send_to_editor(), which is the only one that sympa.pl can run. The 
goal is to generate an HTML version of the messages for later web 
moderation. In you case, the mhonarc call is probably blocking. If you 
can add a trace in List::send_to_editor() you might find out why. It is 
likely that a .mhonarc.lck file is making problems in this list archives.

If I understand you right, you have a sympa.pl hanging, probably waiting 
for a mhonarc child process. Try killing this mhonarc process and see if 
sympa.pl goes back to work. You probably need to remove a .mhonarc.lck 
file to stop these problems.

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