[Zope] zope unresponsive

[Brian Sullivan]

On 2/24/07, Paul Williams <PWilliams at diamonddata.com> wrote:
>
>
>
> I have posted this several times, but have not until now been able to get
> DeadlockDebugger installed.  I see several people have had this problem, but
> no-one has posted a solution.
>
>  zope 2.9.5 + zeo
> pythonm2.4.3
> Red Hat RHEL 4
> Plone 2.5.1
>
> Our zeo clients hang intermittently.  We have no way of reproducing the
> problem, but it occurs daily.  The client hangs and a restart seems to fix
> the
> problem.
>

I don't know if this even relevant but I also have had Zope go into
lala land and struggled for a while trying to figure out what was
going on. Like your situation it happened intermittently and a reboot
recovered (and sometimes seemed to recover on its own). And like you I
tried various methods to spot the problem including installing
DeadlockDebugger.

This was in various versions of Zope running on Win2003.

In the end I found it was a page/browser at the root of the problem.
It turns it is very easy to mount an inadvertent DOS attack on Zope
that kills it. In my case I had a javascript in a periodic timer event
handler (with a fairly short period) that did a page reload and under
certain circumstances didn't clear the timer causing a timer event
driven endless loop.