helpMHonArc - Support: sr #105905, Occasionally, produces a huge xml...

 
 

sr #105905: Occasionally, produces a huge xml output with contents: a rel="><

Submitted by:  Marc Girod <mgirod>
Submitted on:  Tue 19 Jun 2007 04:01:48 PM UTC  
 
Category: NonePriority: 5 - Normal
Severity: 3 - NormalStatus: Done
Privacy: PublicAssigned to: None
Open/Closed: ClosedOperating System: GNU/Linux

Add a New Comment(Rich Markup)
   

You are not logged in

Please log in, so followups can be emailed to you.

 

(Jump to the original submission Jump to the original submission)

Tue 10 Jul 2007 12:47:42 PM UTC, comment #6:

Thanks for your comments.
I now understand that you are right, and that the production of rss feeds must be done otherwise.
My wrapper does not invoke mhonarc with -otherindexes.
I'll consider mharc.
Thank again!
Marc

Marc Girod <mgirod>
Fri 06 Jul 2007 04:26:52 AM UTC, comment #5:

Looking at the mrc file you provided, I saw nothing in
it that indicates mhonarc is responsible for creating
the RSS XML file that seems to be causing you problems.

Are you sure that mhonarc is creating the XML file or
could it be the wrapper/caller script instead?

Is the wrapper calling mhonarc with -otherindexes?

As for alternative configurations, you can see how
mharc, (http://www.mhonarc.org/mharc/), is designed
to process mail. The Install doc provides info on
how and why mharc is setup the way it is.

Note, I do not know if mharc is appropos for what you
have, but the design model of it may give you ideas on how
to change things on your system to make it more scalable
and robust.

Earl Hood <ehood>
Project Administrator
Wed 04 Jul 2007 02:27:30 PM UTC, comment #4:

Actually, I forgot to mention that right now, the generation of rss feeds (and only it) for mail archives is completed stopped, including in the eng-artix-merge archive, and this since June 20.
[I was one week away in the meanwhile].
My last move had been to rename away the huge xml files, and to kill the processes with an open file descriptor on them.

Marc Girod <mgirod>
Wed 04 Jul 2007 01:31:20 PM UTC, comment #3:

Thanks for your feed-back and comments!
I try to answer your questions (1-3), and then add an update (4).

1. the way mhonarc is invoked is indeed as you guessed, on reception of each and every mail:

~> grep mailapp /etc/aliases
eng-mailapp: "| /usr/bin/python /x1/eng-mailapp/bin/mailapp"
~> grep mhonarc /x1/eng-mailapp/bin/mailapp
mhonarc = '/usr/local/bin/mhonarc'
mhonarc_cmd = '%s -quiet -outdir %s -add -rcfile /x1/eng-mailapp/conf/mhonarc.mrc -definevar MAILLISTNAME=%s'
cmd = mhonarc_cmd % (mhonarc, dir, elist)
log.exception('problem with mhonarc child process: %s', str(e))
log.error('%s exited with status %d', mhonarc, rt)
log.error('output from %s was:', mhonarc)
~> wc -l /x1/eng-mailapp/conf/mhonarc.mrc
483 /x1/eng-mailapp/conf/mhonarc.mrc

I attached this mrc file.

Of course, I am open to suggestions to switch to an other configuration.
As far as I can say, the mailapp script dispatches the incoming mails into distinct mailboxes, and runs mhonarc on the relevant one.

2.
~> /usr/local/bin/mhonarc -v
MHonArc v2.6.16 (Perl 5.008005 linux)
Copyright (C) 1995-2005 Earl Hood, -unavailable-
MHonArc comes with ABSOLUTELY NO WARRANTY and MHonArc may be copied only
under the terms of the GNU General Public License, which may be found in
the MHonArc distribution.

3. Isolate an archive... all the errors detected were for the same one (eng-artix-merge which I meantioned), which has also the highest load.
However, I could not isolate a message, or a pattern. This was the intend of my convoluted 'head' commands, but I found different patterns in different cases.

4. We may have a general resource problem on this host. At least one other functionality (generation of rss feeds from wiki pages) is also affected.

Thanks again.

(file #13241)

Marc Girod <mgirod>
Sat 30 Jun 2007 09:20:08 PM UTC, comment #2:

It's hard to provide any insight w/o knowing how mhonarc
is actually invoked and what resource configurations are
being applied.

Knowing the version of mhonarc in use may help also.

Some resource settings can cause a performance hit, and
there has been issues in the past where quirks in perl's
regex engine have been exposed, causing problems (like
infinite loops or consuming memory until things crash).

Your comments imply that archive updates are probably
not done in the most resource efficient manner. If
things are configured to update archives right when messages
arrive, this is generally bad since it does not scale well,
and can lead to bottlenecks as mhonarc processes can queue
up waiting for a lock to release.

I favor a batch model where new messages are processed
on a periodic basis (maybe via cron).

If you can, see if you can isolate which archive and/or
messages causes the problem. This way one can try to
see if the problem can be replicated outside of your
environment.

Earl Hood <ehood>
Project Administrator
Thu 21 Jun 2007 09:48:09 AM UTC, comment #1:

Not occasional anymore...
The situation went back to this mode twice in the last two days.
I tried to identify a pattern before the junk in the ouput, but got different results, found also in the raw mail input.

The size of the raw input may be much smaller that this of the produced xml output (e.g. 2m).

At one point, I found a .mhonarc.lck directory, always empty, but with a recent, and updated timestamp.
I am not sure what produces it, when and why.
lsof on it didn't give anything.
Its presence blocks the updating of .mhonarc.db

eng-artix-merge> sudo wc .mhonarc.db
102197 311633 4857936 .mhonarc.db

Marc Girod <mgirod>
Tue 19 Jun 2007 04:01:48 PM UTC, original submission:

Hello,

I took over the maintenance of our internal web site.
There we use mhonarc to archive mailing lists, and generate rss feeds.
We use it from a python wrapper, named mailapp, which I believe was written in-house.

Occasionally (Feb 21, June 18), one process starts taking up all the host resources (80% of the memory, significant CPU share).
The number of mailapp processes raises--my understanding is that the topmost is not releasing a lock, and new ones are just cropping.

I can then find two files of huge sizes (20M):
- rawmsgs.txt
- rss20.xml

Renaming them away, and killing the processes solves the problem temporarily.

Looking at the contents of the xml file, I found beyond the first 100k a repeated pattern of:

a rel="&gt;&lt;

eng-artix-merge> head -c 101100 rss20.xml.away | tail -c 100; echo
-0,0 +1,99 @@&lt;br /&gt;+&lt;a rel="&gt;&lt;a rel="&gt;&lt;a rel="&gt;&lt;a rel="&gt;&lt;a rel="&g

I am not sure what is the cause and what the effects.
I couldn't find an existing report which would clearly describe the same problem.
Any insights are welcome.

Marc

Marc Girod <mgirod>

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach File(s):
   
   
Comment:
   

Attached Files
file #13241:  mhonarc.mrc added by mgirod (15KiB - application/octet-stream)

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -unavailable- added by ehood (Posted a comment)
  • -unavailable- added by mgirod (Submitted the item)
  •  

    Do you think this task is very important?
    If so, you can click here to add your encouragement to it.
    This task has 0 encouragements so far.

    Only logged-in users can vote.

     

    Please enter the title of George Orwell's famous dystopian book (it's a date):

     

     

    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Mon 03 Jan 2011 05:20:11 PM UTCehoodStatusNone=>Done
      Open/ClosedOpen=>Closed
    Wed 04 Jul 2007 01:31:20 PM UTCmgirodAttached File-=>Added mhonarc.mrc, #13241

    Back to the top


    Powered by Savane 3.1-cleanup1