ZODB3 3.3 alpha 2 released (original) (raw)

Jeremy Hylton jeremy@zope.com
Tue, 06 Jan 2004 23:41:09 -0500

I'm pleased to announce the release of ZODB2 3.3 alpha 2. This release includes support for new-style persistent classes and multi-version concurrency control. It's an alpha release, so we could use feedback on the new features and helping testing them.

The 3.3a2 release requires Python 2.3. It contains the code that is slated to be in Zope 2.8.

You can download a source tarball or Windows installer from http://zope.org/Products/ZODB3.3

The new features represent major changes to ZODB. Support for new-style classes means that ZODB programmers can use the new class features introduced in Python 2.2, like properties and descriptors. It also means that ZODB no longer uses ExtensionClass, which caused many subtle incompatibilities with other classes.

The multi-version concurrency control feature represents the end of read conflicts. If a transaction encounters a conflict, it reads older revisions of the object rather than raising a ReadConflictError. This feature allows read-only transactions to see a consistent view of the database without need to handle read conflicts and restart the transaction.

The code is fairly stable, but we have noted a few hard-to-provoke bugs during development. One problem is a refcount problem in the persistence core that causes rare core dumps in Python's garbage collector. (Rare means once a week across multiple developers and testers.)

We hope to move to a beta release expeditiously, perhaps as early as next month. The final release schedule depends on the Zope 2.8 release schedule. More on that later.

Enjoy!

-- Jeremy Hylton <http://www.python.org/~jeremy/>