[Zope] ZEO troubles on RedHat EL4 Linux

[Andreas Krasa // WUW]

Tim Peters schrieb:
> [Andreas Krasa]
> 
>>We are encountering some really strange problems with Zope 2.7.7 on our
>>RedHat EL 4 Linux machines.
>>
>>During the Zope 2.7.7 compilation works - however most of the time "make
>>test" returns a random number of errors (somewhere between 20 and 30)
>>ALL related to ZEO.
>>
>>The funny thing is, we've managed to do a "make test" without any
>>failures - however after doing a "make distclean" and compiling
>>everything again "make test" produces the above mentioned errors (using
>>*exactly* the same source code!).
>>
>>I have absolutely no idea how this can happen - ANY hints are
>>appreciated! Is this a known issue?
> 
> 
> No.  For example, it doesn't happen in the daily overnight testrunner reports.
> 
> 
>>What could it be related to?
> 
> 
> ZEO <wink>?  You'll have to give more info about which tests fail, and
> precisely how they fail.  Because many of the ZEO tests create
> multiple processes, and try to assign sockets so that these processes
> can communicate, they're vulnerable to vagaries of OS process
> scheduling and socket use by other apps.  For example, on a slow or
> overburdened (with other simultaneous work) machine, some ZEO tests
> can fail due to not getting enough cycles soon enough.  The worst
> tests of that sort wait as long as a minute now for another process to
> "do something" they're waiting for before failing, but not even
> waiting a minute can _guarantee_ success.
> 
> Might be informative to run the tests on an otherwise-quiet machine.

Thank you Tim for the feedback!

Our system is a Intel Xeon 3 GHz Dual-CPU with 2.5 GB RAM running
RedHat Enterprise Linux 4 (SElinux disabled).

As this is a test-machine it doesn't run any CPU-consuming tasks I can
think of - the server load is usually somewhere between 0.00 and 0.10.

But I'll check that nevertheless!

Best regards
Andreas