[Zope-dev] Zope hangs, with processes being idle ... (rather urgent problem)

[Joachim Werner]

>  > I have a Zope 2.5.1 using ZEO on Linux, with Apache as proxy server.
The two
>  > ZEO clients run fine for a couple of hours, and then suddenly one of
them
>  > stops responding. It's the type of Zope hangs when all processes are
fine,
>  > but ZServer just doesn't respond (load is very low, with the CPU 90%
idle,
>  > so it is not a performance issue or recursion problem).
>  >
>  > There is no error before this situation happens. The processes just
don't
>  > respond any more. The second ZEO keeps running, but that machine also
hangs
>  > from time to time, so I guess ZEO is not the problem, and the hardware
or
>  > any Linux-specific problems aren't either.
>  >
>  > When the ZServer hangs, I can not access it directly, so it is no
problem
>  > with the Apache.
>  >
>  > You see, I don't have any clue on what is happening here. The servers
worked
>  > fine for months, and I don't know what specific change could have
caused the
>  > problem.

>  > How can such a situation be debugged?

Dieter Maurer wrote:
> Maybe, you use the "-M" logging and analyse the log with Chris'
> "requestprofiler". You may see unfinished requests.

Thanks! That's what I did. I think I found the problem: I have some Objects
that inherit from Image, and their "data" attribute (that's where the image
data is held) wasn't initialized correctly in some cases. So whenever
somebody tried to display one of those objects, Zope started streaming back
the image data, which made the request hang when the data attribute was
broken.

Cheers

Joachim