[Zope] Re: Zope freeze issue

[Florent Guillaume]

For this class of problem, DeadlockDebugger should come to the rescue.

Florent

Gaël Le Mignot wrote:
> Hello Zope users !
> 
> We are  deploying a Zope on  a customer's server, but  we have regular
> freeze (Zope stop  to answer any requests). The  Zope is running Plone
> 2.1 with some custom products.
> 
> Here are all the informations I gathered on the issue:
> 
> - Zope version 2.8.4
> - Plone version 2.1.1
> - Python version 2.3.5
> - OS: Debian GNU/Linux, sarge, 2.6.8-smp kernel
> - Computer: dual Xeon with 4Gb of memory
> - Zope is behind Apache configured as reversed proxy
> 
> Symptoms:
> 
> - The Zope stops to answer incoming http request on regular intervals
> 
> - When this happens,  the CPU isn't used mch (about  2% used), and the
>   memory isn't full (1Gb used on the 4Gb total)
> 
> - Inspecting the Python  process with gdb shows a  normal operation: a
>   running  thread, and  others  waiting  in, and  then  after a  while
>   (dettaching gdb, waiting a  bit, and reattaching gdb) another thread
>   running. The other threads are in:
> 
> #0  0x40026d0b in sem_wait at GLIBC_2.0 () from /lib/tls/libpthread.so.0
> #1  0x00000004 in ?? ()
> #2  0x080d29de in PyThread_acquire_lock (lock=0x87b1e70, waitflag=1)
>     at thread_pthread.h:406
> 
> - Looking at netstat  shows a few established connections  to the Zope
>   process, but not much (2-3 on avergae)
> 
> What we tried:
> 
> - We tried using ZEO, didn't change anything
> 
> - We tried with the default 4 threads, with 10 threads, and with up to
>   40 threads, nothing changed
> 
> I'm currently out of ideas to  investigate this issue. Does any of you
> have an idea of why could this happen ? Or an idea of what I could try
> to undersatnd what's happening ? Any idea is dearly welcomed.
> 
> Thanks a lot !
> 


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Florent Guillaume, Nuxeo (Paris, France)   CTO, Director of R&D
+33 1 40 33 71 59   http://nuxeo.com   fg at nuxeo.com