[ZODB-Dev] RE: [Zope-Annce] ZODB 3.2.4 release candidate 1released

[Dieter Maurer]

Tim Peters wrote at 2004-9-7 20:53 -0400:
> ...
>I don't know of a scenario in current ZODB wherein catching something can
>make a database inconsistent.  I understand there are persistent rumors that
>it can happen, but requests for a specific case have gone unanswered.

Shane provided one.

Here is another trivial one.

     obj.persistentAttr1 = 1
     ...
     # raise an exception here
     ...
     obj.persistenAttr2 = obj.persitentAttr1

This snipped allows to assume an invariant: after any transaction
"persistentAttr2 == persistentAttr1".

Now let someone catch the exception (withou reraising this or another
one) -- invariant violated.

The example (of course) means application related consistency
and not internal consistency.

-- 
Dieter