[Zope] Counting threads

[Jens Vagelpohl]

On Jan 22, 2008, at 23:33 , Peter Bengtsson wrote:

> On 22/01/2008, Dieter Maurer <dieter at handshake.de> wrote:
>> Peter Bengtsson wrote at 2008-1-22 15:23 +0000:
>>> Perhaps I'm wrong but I suspect that a Zope I'm running is dying  
>>> because
>>> of running out of threads.
>>
>> This is very unlikely. It may no longer respond when all its threads
>> are working -- but it will not die for this reason.
>>
> By dying I don't mean crashing and stopping but instead staying up and
> running but not responding to anything. Like a coma.

This symptom, especially when these "hanging" threads cause no load at  
all on the system, certainly point to connections to outside systems  
that do not respond for some reason. I have seen this issue with Zope  
instances that make HTTP calls to other systems, or even with a  
hanging LDAP server which accepted connections from Zope but never  
returned. Any software that makes outgoing network connections from  
Zope is a potential suspect.

GDB can help you determine where the hanging condition originates.  
Here's some links:

http://plone.org/documentation/how-to/use-gdb-to-get-backtraces-of-hung-spinning-sites

http://zopelabs.com/cookbook/1073504990

jens