[ZODB-Dev] updating BTrees

[Jeremy Hylton]

On Tue, 2003-04-29 at 12:44, Chris Withers wrote:
> Jeremy Hylton wrote:
> > I think "bit of a mess" may be an understatement :-).
> > 
> > ZODB3 and ZODB4 are entirely incompatible because the persistence
> > implementations use ExtensionClass and new-style classes, respectively. 
> > There's no practical way to mix them.
> 
> What's the proposed upgrade path for going from ZODB3 to ZODB4?

It's hard to say in a lot of detail.

When ZODB4 is stable, we'll develop a tool to copy transactions from a
ZODB3 database to a ZODB4 database.  That seems like the easy part to
me.

Applications will also need to be updated to use the new ZODB4
interfaces.  I don't have a good sense for how hard this will be.  Jim
tells me that most Zope apps don't use the ZODB interfaces directly, so
it shouldn't be too hard to port applications.

If you've got a more specific use case -- like "I want to migrate this
particular app" -- I might be able to say more.

Jeremy