I'm pleased to announce the release of ZODB 3.2 alpha 1. This release includes many new features, some of them still a little experimental. You'll find a faster ZEO server with a simpler command-line script to run it. There's also a new configuration package, called ZConfig, which will eventually be included in Zope, too. In keeping with 3.x releases, some obscure BTrees bugs have been fixed. I expect there will be another alpha release as we refine the experimental features and finish other proposed new features. See the release plan in the ZODB Wiki at http://www.zope.org/Wikis/ZODB. You can download a source release and Windows installers from http://www.zope.org/Products/StandaloneZODB I've included the most recent entries from NEWS.txt below. Jeremy What's new in ZODB3 3.2 alpha 1 =============================== Release date: 17-Jan-2003 Most of the changes in this release are performance and stability improvements to ZEO. A major packaging change is that there won't be a separate ZEO release. The new ZConfig is a noteworthy addtion (see below). ZODB ---- An experimental new transaction API was added. The Connection class has a new method, setLocalTransaction(). ZODB applications can call this method to bind transactions to connections rather than threads. This is especially useful for GUI applications, which often have only one thread but multiple independent activities within that thread (generally one per window). Thanks to Christian Reis for championing this feature. Applications that take advantage of this feature should not use the get_transaction() function. Until now, ZODB itself sometimes assumed get_transaction() was the only way to get the transaction. Minor corrections have been added. The ZODB test suite, on the other hand, can continue to use get_transaction(), since it is free to assume that transactions are bound to threads. ZEO --- There is a new recommended script for starting a storage server. We recommend using ZEO/runzeo.py instead of ZEO/start.py. The start.py script is still available in this release, but it will no longer be maintained and will eventually be removed. There is a new zdaemon implementation. This version is a separate script that runs an arbitrary daemon. To run the ZEO server as a daemon, you would run "zdaemon.py runzeo.py". There is also a simple shell, zdctl.py, that can be used to manage a daemon. Try "zdctl.py -p runzeo.py". There is a new version of the ZEO protocol in this release and a first stab at protocol negotiation. (It's a first stab because the protocol checking supporting in ZODB 3.1 was too primitive to support anything better.) A ZODB 3.2 ZEO client can talk to an old server, but a ZODB 3.2 server can't talk to an old client. It's safe to upgrade all the clients first and upgrade the server last. The ZEO client cache format changed, so you'll need to delete persistent caches before restarting clients. The ZEO cache verification protocol was revised to require many fewer messages in cases where a client or server restarts quickly. The performance of full cache verification has improved dramatically. XXX Get measurements from Jim -- somewhere in 2x-5x recall. The implementation was fixed to use the very-fast getSerial() method on the storage instead of the comparatively slow load(). The ZEO server has an optional timeout feature that will abort a connection that does not commit within a certain amount of time. The timeout works by closing the socket the client is using, causing both client and server to abort the transaction and continue. This is a drastic step, but can be useful to prevent a hung client or other bug from blocking a server indefinitely. A bug was fixed in the ZEO protocol that allowed clients to read stale cache data while cache verification was being performed. The fixed version prevents the client from using the storage until after verification completes. The ZEO server has an experimental monitoring interface that reports usage statistics for the storage server including number of connected clients and number of transactions active and committed. It can be enabled by passing the -m flag to runsvr.py. The ZEO ClientStorage no longer supports the environment variables CLIENT_HOME, INSTANCE_HOME, or ZEO_CLIENT. The ZEO1 package is still included with this release, but there is no longer an option to install it. BTrees ------ The BTrees package now has a check module that inspects a BTree to check internal invariants. Bugs in older versions of the code code leave a BTree in an inconsistent state. Calling BTrees.check.check() on a BTree object should verify its consistency. (See the NEWS section for 3.1 beta 1 below to for the old BTrees bugs.) Fixed a rare conflict resolution problem in the BTrees that could cause an segfault when the conflict resolution resulted in any empty bucket. Installation ------------ The distutils setup now installs several Python scripts. The runzeo.py and zdaemon.py scripts mentioned above and several fsXXX.py scripts from the Tools directory. The test.py script does not run all the ZEO tests by default, because the ZEO tests take a long time to run. Use --all to run all the tests. Otherwise a subset of the tests, mostly using MappingStorage, are run. Storages -------- There are two new storages based on Sleepycat's BerkeleyDB in the BDBStorage package. Barry will have to write more here, because I don't know how different they are from the old bsddb3Storage storages. See Doc/BDBStorage.txt for more information. It now takes less time to open an existing FileStorage. The FileStorage uses a BTree-based index that is faster to pickle and unpickle. It also saves the index periodically so that subsequent opens will go fast even if the storage was not closed cleanly. Misc ---- The new ZConfig package, which will be used by Zope and ZODB, is included. ZConfig provides a configuration syntax, similar to Apache's syntax. The package can be used to configure the ZEO server and ZODB databases. See the module ZODB.config for functions to open the database from configuration. See ZConfig/doc for more info. The zLOG package now uses the logging package by Vinay Sajip, which will be included in Python 2.3. The Sync extension was removed from ExtensionClass, because it was not used by ZODB.