[ZODB-Dev] Another interesting ZODB cache inconsistency

Dieter Maurer dieter at handshake.de
Sun Jan 15 14:29:27 EST 2006


Jim Fulton wrote at 2006-1-13 17:54 -0500:
> ...
>> This means that interrupting ZEO while it is sending invalidation messages
>> can cause inconsitent states in the ZODB caches of its clients.
>
>What do you mean by inconsistent states?  Do you mean inconsistent
>between clients?

The inconsistent ZEO clients were in fact Zopes.

   Viewing the same page (via the same Zope) repeatedly sometimes
   showed the old and sometimes the new state.

   I concluded that some ZODB caches must still contain the old
   while others already contain the new state.

   The inconsistency was thus already within a single ZEO client.


   I agree that this contradicts my previous assumption
   that partial reception of invalidation messages were to blame
   because all DB's in a single ZEO client receive the invalidation
   messages at the same time.


-- 
Dieter


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