[ZODB-Dev] Question about BTree transaction data

Pascal Peregrina Pperegrina at Lastminute.com
Wed Apr 12 03:35:37 EDT 2006


I use FileStorage (via ZEO).

I have switched a big dictionary from PersistentMapping to BTree.

In the past, it was easy to compute added/deleted keys from states (cause PersistentMapping state contains the whole dictionary, so it was only a matter of getting the keys and comparing them with previous state keys).

I can't see how to do so with BTree states, which look much more complicated... So could you give me a little more details about what you mean? (or of course point me to some example/resources on the net)

Thanks.

Pascal

-----Message d'origine-----
De : Dieter Maurer [mailto:dieter at handshake.de] 
Envoyé : mardi 11 avril 2006 21:57
À : Pascal Peregrina
Cc : zodb-dev at zope.org
Objet : Re: [ZODB-Dev] Question about BTree transaction data

Pascal Peregrina wrote at 2006-4-10 09:04 +0100:
>I would like to know if from BTree state data, it is possible to compute
>which keys were added/deleted.

Of course not from a single state: it just tells you about the
current keys, not about their history.

If you are using a storage with history (e.g. "FileStorage"),
then the history can allow you to retrieve earlier states.
Comparing the current and some earlier state allows you to
determine additions/deletions (to some extend).

-- 
Dieter


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