[Zope] Zope hangs and Python eats all memory

[Nico Grubert]

Dear list members,

I am running Zope 2.9.6. on a 64-Bit Suse Linux 10.1 machine (9 Gbyte of 
RAM) with Python 2.4.3. installed.
 From time to time, Zope hangs and I cannot access it anymore. I tried 
to use the "Zope DeadlockDebugger" but if my Zope hangs I cannot call 
the URL "http://myzopesite:8080/manage_debug_threads?secret_password" to 
let Zope DeadlockDebugger show any useful information. Zope does not 
response.
If Zope hangs, the python process eats all the memory and the machine 
starts to swap.

The "top" command in the shell tells me: 
-------------------------------------------------------------------------
Tasks:  91 total,   2 running,  89 sleeping,   0 stopped,   0 zombie
Cpu(s): 10.4%us,  0.4%sy,  0.0%ni, 89.0%id,  0.2%wa,  0.0%hi,  0.0%si
Mem:   9041256k total,  9025124k used,    16132k free,    10604k buffers
Swap:  4208988k total,  4208988k used,        0k free,     9472k cached

   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND 

29992 wwwrun    16   0 12.0g 8.3g 2860 S   19 95.9   3:52.66 python
-------------------------------------------------------------------------

There are several add-ons for Zope installed, like:
  - "Psycopg" Postgres Database Adapter
  - "mxODBCDA" ODBC Database Adapter
  - LDAPUserfolder
  - "Silva" Content Management System
  - PIL

Furthermore, I see a lot of Conflict Errors in the "event.log" like e.g.:
-------------------------------------------------------------------------
ZPublisher.Conflict ConflictError at 
/VirtualHostBase/http/193.134.202.20:80/mysite/VirtualHostRoot/: 
database conflict error (oid 0x0435, class BTrees._OOBTree.OOBTree, 
serial this txn started with 0x036aeb14ab1c4b88 2007-01-15 
12:04:40.104030, serial currently committed 0x036aeb1d0cc5d099 
2007-01-15 12:13:02.993605) (80 conflicts (0 unresolved) since startup 
at Mon Jan 15 11:44:55 2007)
-------------------------------------------------------------------------

These kind of Conflict errors occur almost every minute.
It might be that these errors have something to do with it but I am not 
sure.

How can I figure out what exactly causes Zope to hang?
If you need more information, please let me know.

Thanks in advance...

Regards,
Nico