[Zope] ZServer lockups

[Paul Everitt]

And one other debugging thing to look for: when it's hung, check to see
if the process is consuming much CPU.

--Paul

> -----Original Message-----
> From: Amos Latteier [mailto:amos@aracnet.com]
> Sent: Thursday, August 12, 1999 5:23 PM
> To: Jonas Juselius; jason@brahms.siteprotect.com; Robin Becker
> Cc: zope@zope.org
> Subject: Re: [Zope] ZServer lockups
> 
> 
> 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
> 
> 
> 
> 
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