Last month I ask for help about hanging zeo clients. I promised to follow up.

Dieter Maurer wrote:
Anton Stonor wrote at 2008-4-7 16:16 +0200:
We have a setup with a ZEO server and 4 ZEO clients.

During the last weeks we have seen almost daily deadlocks in some of the ZEO clients. I've tried to wait for up to 30 minutes before restarting a client.

I could need an advice on how to debug this.

With DeadlockDebugger I see the same pattern each time:

One thread is hanging:
    r_flags, r_args = self.wait(msgid)
File "/usr/local/www/zope-2.9.6/lib/python/ZEO/zrpc/", line 638, in wait

This means that the client is waiting for a reply -- which apparently
does not come.

Maybe some router or firewall sometimes drops packages and connections?

It was a hardware issue. /var/log/messages was full of random "link state changed to DOWN". The unstable net connection was caused by a unstable switch.


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