Commit 0333a534 authored by Jeremy Hylton's avatar Jeremy Hylton

Update the NEWS file for the 3.3a3 release.

parent b48fa673
......@@ -2,9 +2,123 @@ What's new in ZODB3 3.3 alpha 3
===============================
Release date: 16-Apr-2004
FileStorage
transaction
-----------
There is a new transaction package, which provides new interfaces for
application code and for the interaction between transactions and
resource managers.
The top-level transaction package has functions commit(), abort(),
get(), and begin(). They should be used instead of the magic
get_transaction() builtin, which will be deprecated. For example:
>>> get_transaction().commit()
should now be written as
>>> import transaction
>>> transaction.get()
The new API provides explicit transaction manager objects. The
transaction manager (TM) is responsible for associating resource
managers with a "current" transaction. It is available as
`transaction.manager`. The default TM, implemented by
ThreadedTransactionManager, assigns each thread its own current
transaction. The TransactionManager class assigns all threads to the
same transaction.
A transaction manager instance can be passed as the txn_mgr argument
to DB.open(). If you do, the connection will use the specified
transaction manager instead of the default transaction manager. You
will need to call commit() and abort() on the transaction manager
explicitly. For example:
>>> tm = transaction.TransactionManager()
>>> cn = db.open(txn_mgr=tm)
[...]
>>> tm.commit()
The setLocalTransaction() and getTransaction() methods of Connection
are deprecated. Use an explicit TM passed via txn_mgr instead. The
setLocalTransaction() manager functions still works, but it returns a
TM instead of a Transaction.
The TM creates Transaction objects, which are used for exactly one
transaction. They have a status() method that returns their current
state.
Resource managers, e.g. Connection or RDB adapter, should use join()
instead of register(). An object that calls join() manages its own
resources. An object that calls register() expects the TM to manage
the objects.
Data managers written against the ZODB 4 transaction API are now
supported in ZODB 3.
persistent
----------
A database can now contain persistent weak references. An object that
is only reachable from persistent weak references will be removed by
pack().
The persistence API now distinguishes between deactivation and
invalidation. This change is intended to support objects that can't
be ghosts, like persistent classes. Deactivation occurs when a user
calls _p_deactivate() or when the cache evicts objects because it is
full. Invalidation occurs when a transaction updates the object. An
object that can't be a ghost must load new state when it is
invalidated, but can ignore deactivation.
Persistent objects can implement a __getnewargs__() method that will
be used to provide arguments that should be passed to __new__() when
instances (including ghosts) are created. An object that implements
__getnewargs__() must be loaded from storage even to create a ghost.
There is new support for writing hooks like __getattr__ and
__getattribute__. The new hooks require that user code call special
persistence methods like _p_getattr() inside their hook. See the ZODB
programming guide for details.
The format of serialized persistent references has changed; that is,
the on-disk format for references has changed. The old format is
still supported, but earlier versions of ZODB will not be able to read
the new format.
ZODB
----
Closing a ZODB Connection while it is registered with a transaction,
e.g. has pending modifications, will raise a ConnnectionStateError.
Trying to load objects from or store objects to a closed connection
will also raise a ConnnectionStateError.
ZODB connections are synchronized on commit, even when they didn't
modify objects. This feature assumes that the thread that opened the
connection is also the thread that uses it. If not, this feature will
cause problems. It can be disabled by passing synch=False to open().
New broken object support.
New add() method on Connection. User code should not assign the
_p_jar attribute of a new persistent object directly; a deprecation
warning is issued in this case.
Added a get() method to Connection as a preferred synonym for
__getitem__().
Several methods and/or specific optional arguments of methods have
been deprecated. The cache_deactivate_after argument used by DB() and
Connection() is deprecated. The DB methods getCacheDeactivateAfter(),
getVersionCacheDeactivateAfter(), setCacheDeactivateAfter(), and
setVersionCacheDeactivateAfter() are also deprecated.
The old-style undo() method was removed from the storage API, and
transactionalUndo() was renamed to undo().
The BDBStorages are no longer distributed with ZODB.
Fixed a serious bug in the new pack implementation. If pack was
called on the storage and passed a time earlier than a previous pack
time, data could be lost. In other words, if there are any two pack
......@@ -40,15 +154,67 @@ zdaemon
Added a -m / --mask option that controls the umask of the subprocess.
zLOG
----
The zLOG backend has been removed. zLOG is now just a facade over the
standard Python logging package. Environment variables like
STUPID_LOG_FILE are no longer honored. To configure logging, you need
to follow the directions in the logging package documentation. The
process is currently more complicated than configured zLOG. See
test.py for an example.
ZConfig
-------
This release of ZODB contains ZConfig 2.1.
More documentation has been written.
Make sure keys specified as attributes of the <default> element are
converted by the appropriate key type, and are re-checked for derived
sections.
Refactored the ZConfig.components.logger schema components so that a
schema can import just one of the "eventlog" or "logger" sections if
desired. This can be helpful to avoid naming conflicts.
Added a reopen() method to the logger factories.
Always use an absolute pathname when opening a FileHandler.
Miscellaneous
-------------
The layout of the ZODB source release has changed. All the source
code is contained in a src subdirectory. The primary motivation for
this change was to avoid confusion caused by installing ZODB and then
testing it interactively from the source directory; the interpreter
would find the uncompiled ZODB package in the source directory and
report an import error.
A reference-counting bug was fixed, in the logic calling a modified
persistent object's data manager's register() method. The primary symptom
was rare assertion failures in Python's cyclic garbage collection.
The Connection class's onCommitAction() method was removed.
Some of the doc strings in ZODB are now written for processing by
epydoc.
Several new test suites were written using doctest instead of the
standard unittest TestCase framework.
MappingStorage now implements getTid().
ThreadedAsync: Provide a way to shutdown the servers using an exit
status.
The mkzeoinstance script looks for a ZODB installation, not a Zope
installation. The received wisdom is that running a ZEO server
without access to the appserver code avoids many mysterious problems.
What's new in ZODB3 3.3 alpha 2
===============================
......
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