Mnesia deadlock?

Claes Wikstom klacke@REDACTED
Fri Dec 30 09:59:15 CET 2005

Adam Aquilon wrote:
> Hi there!
> Hope someone out there (Klacke, Dan?) understands something about this:
> We seemed to get a deadlock in Mnesia. All mnesia calls on one of the
> nodes hung forever.
> ......
> All mnesia-related calls to the main node (the one performing the backup)
> that we tried hung. Including things like mnesia:system_info().

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.

We recently had a mnesia deadlock in our system - but that wasn't
mnesias fault. We were doing gen_server calls from within transactions
to other servers which we're also doing transactions ... thus we
deserved the deadlock.

If mnesia:info() doesn't work though - all the more reason to
have a look at the individual processes and figure out what they do -
or rather what they don't and why.


Claes Wikstrom                        -- Caps lock is nowhere and                  -- everything is under control
cellphone: +46 70 2097763

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