[ZODB-Dev] server stops handling requests - nowhere near 100% CPU or Memory used

[Claudiu Saftoiu]

On Thu, Apr 19, 2012 at 11:33 AM, Martijn Pieters <mj at zopatista.com> wrote:

> On Thu, Apr 19, 2012 at 17:20, Claudiu Saftoiu <csaftoiu at gmail.com> wrote:
> > My question is: what could possibly be causing the server to 'lock up',
> even
> > on a
> > simple view like 'is_alive', without using any memory or CPU? Is there
> some
> > ZODB
> > resource that might be getting gradually exhausted because I'm not
> handling
> > it properly?
>
> I don't know, anything could lock up your site if something is waiting
> for a lock, for example.
>

Are there locks that could possibly be used for the 'is_alive' function?
Here is the
definition in its entirety.

In 'configure.zcml':
  <view
    view=".views.is_alive"
    name="is_alive"
    renderer="json"
    />
in 'views.py':
    def is_alive(request):
        return True

Whatever the problem is, it causes 'is_alive' to take forever, and the CPU
is not
spinning at 100%, and memory usage is not high. Could this be a lock
problem?

Use http://pypi.python.org/pypi/z3c.deadlockdebugger to figure out
> what the threads are doing at this time. Preferably, trigger the
> dump_threads() method of that module on SIGUSR1, like the Zope
> signalstack product does (see
>
> http://svn.plone.org/svn/collective/Products.signalstack/trunk/Products/signalstack/__init__.py
> for the exact code to bind the signal handler). That'll tell you
> exactly what each thread is busy with when you send the signal.
>

Thanks, I'll check this out.
- Claudiu
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