Mnesia deadlock?

Adam Aquilon <>
Fri Dec 30 16:35:28 CET 2005


On Fri, 30 Dec 2005 09:59:15 +0100, Claes Wikstom <> wrote:
> Fishy, What you should have done is to do a process listsing i()
> and figured out which processes were waiting for which.
> The suspicios process you should do  a backtrace on to get
> the stacks.

I've finally managed to make mnesia hang again.

It's wierd -- we tried to recreate all the conditions of yesterday:
sending continuous requests to the system, running dumps and backups
very often, messing about with the disk_log server on another node
(on the same host), etc, etc.

Nothing we did could make it crash, not even 100 % CPU load and
simultaneous reading from a 1 GB disk_log and converting it to a
text file in /tmp!

Eventually we got fed up and went for a coffe. When we came back,
the system had gone back into the "bad" state. Notice that it is only
the mnesia subsystem on the main node that is hanging. Everything
else is still running as before, so the text file backtraces I've
attached haven't all been taken in a static system (even though the
hung processes are pretty "stable" :-).

I included both the "i()" output from the failed node as well as
backtraces from a number of processes that could maybe be of interest
to you.

I'll try to leave the system in this state. I could even provide
ssh login to you if that'll help.


Regards,
Adam Aquilon,
Cellpoint
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