[Zope] ZServer lockups

[Amos Latteier]

At 11:23 AM 8/11/99 +0300, Jonas Juselius wrote:
>I'm experiencing the same kind of problems, although I'm using the Zope
server
>(no Apache)... Netscape seems to lock up waiting for data infinitely.  I can
>usually get around this problem by re-clicking on a url a couple of times,
>which resolves the problem for the moment. But after ZServer has gone into
>this state, it locks up again and again until ZServer is restarted... I'm
>using Zope-2.0.0b3-linux2-x86.
>
>jonas
>
>On Tue, Aug 10, 1999 at 12:33:56PM -0500, jason@brahms.siteprotect.com wrote:
>> 
>> I'm experiencing occasional lockups of ZServer (currently being
>> used in conjuction with PCGI and Apache).  When this happens, I get
>> no response at all from the http interface (Netscape eventually times
>> out and says the document contains no data).  

A number of folks have posted about Zope lock up issues. It is very
important to me to resolve this issues.

If any of you can reproduce a Zope lock up, please, please, please, submit
this issue to the Collector, ASAP.

Tracking down problems like these can be difficult. There are lots of
things that can go wrong which could cause Zope to stop responding, for
example serious problems in any of these areas could halt Zope:

  * ZServer
  * The Zope process itself
  * The object database

When ZServer occasionally locks up for me, it usually because I did
something that's causing the publishing process to hang. This happens when
you are coding external methods or Python products and make certain kinds
of mistakes that put Zope in a loop.

If ZServer itself breaks usually you will get something written to the info
log, or else ZServer will exit with a traceback. If you suspect that
ZServer is the problem try running it with the -D switch so that the info
logging goes to the STDOUT and so you can read the traceback in case it exits.

If you think that your object database is messed up you can test things by
using the scripts in the utilities directory. You can also use the monitor
to poke around at objects and check out if their state is weird.

In general if you've got an object database problem you should still be
able to connect to the ZServer monitor and ftp servers which does not
immediately rely on the object database.

If Zope is completely unresponsive, then there's not a lot you can do
except kill the process. If you can kill it in the foreground with a
control-c then you will get a traceback which may give you some clue as to
what was wrong.

So to reiterate: If you can reproduce a lockup submit it to the Collector.
If you are developing external methods or Products there is a good chance
the your code is causing the problem. If not, poke around and see what you
can find, and post your findings to the Zope list, with enough information
we should be able to solve the problem.

Good luck!

-Amos