[ZODB-Dev] Deadlock in ZODB/DB.py?

[Tim Peters]

[Christian Zagrodnick]
> the DB.open method makes me wonder how it works (http://svn.zope.org/
> ZODB/trunk/src/ZODB/DB.py?rev=69551&view=auto)
>
> It locks with self._a() and calls self._connectionMap which locks
> too. I cannot imagine a way this could possibly work.

Look at __init__():

        x = threading.RLock()
        self._a = x.acquire
        self._r = x.release

That is, it's a reentrant lock.  See the Python docs for RLock().

> I guess the lock should be released before the _connectionMap call?

No.

> Interestingly both all the tests pass and ZODB works...

That was a good clue ;-)