[ZODB-Dev] ZODB file never updated - import transaction fails...

[Dieter Maurer]

skip at pobox.com wrote at 2006-7-29 08:40 -0500:
> ...
>When the cache is deleted, its __del__ method calls
>
>    self.close()
>
>which calls self._zodb_close():
>
>  def _zodb_close(self):
>      # Ensure that the db is saved before closing.  Alternatively, we
>      # could abort any waiting transaction.  We need to do *something*
>      # with it, though, or it will be still around after the db is
>      # closed and cause problems.  For now, saving seems to make sense
>      # (and we can always add abort methods if they are ever needed).
>      self._zodb_store()
>
>      # Do the closing.        
>      self._DB.close()
>
>which calls self._zodb_store():
>
>  def _zodb_store(self):
>      import transaction
> ...
>which seems to fail.  I get this message in the log:
>
>    Exception exceptions.ImportError: 'No module named transaction' in
>    <bound method cache.__del__ of <spambayes.dnscache.cache instance at
>    0x11994b8>> ignored

Is the cache deleted when Python terminates?

At this time, Python no longer works reliable as resources
must be released in some order and after a resource is released
it cannot be used anymore. In your case, "sys.path" might have
been released when the destructor tries to import "transaction".
It will fail then.

Avoid using "__del__" and call your close explicitely.


-- 
Dieter