Metadata-Version: 1.1
Name: ZODB3
Version: 3.9.7
Summary: Zope Object Database: object database and persistence
Home-page: UNKNOWN
Author: Zope Foundation and Contributors
Author-email: zodb-dev@zope.org
License: ZPL 2.1
Description: The Zope Object Database provides an object-oriented database for
        Python that provides a high-degree of transparency. Applications can
        take advantage of object database features with few, if any, changes
        to application logic.  ZODB includes features such as a plugable storage
        interface, rich transaction support, and undo.
        
        
        .. contents::
        
        ====
        ZODB
        ====
        
        Introduction
        ============
        
        The ZODB  package provides a  set of tools  for using the  Zope Object
        Database (ZODB).  The components you  get with the ZODB release are as
        follows:
        
        - Core ZODB, including the persistence machinery
        - Standard storages such as FileStorage
        - The persistent BTrees modules
        - ZEO, for scalability needs
        - documentation (needs a lot more work)
        
        Our primary development platforms are Linux, Mac OS X, and Windows
        XP.  The test suite should pass without error on all of these
        platforms, although it can take a long time on Windows -- longer if
        you use ZoneAlarm.  Many particularly slow tests are skipped unless
        you pass --all as an argument to test.py.
        
        Compatibility
        =============
        
        ZODB 3.9 requires Python 2.4.2 or later.
        
        Note --
           When using ZEO and upgrading from Python 2.4, you need to upgrade
           clients and servers at the same time, or upgrade clients first and
           then servers.  Clients running Python 2.5 or 2.6 will work with
           servers running Python 2.4.  Clients running Python 2.4 won't work
           properly with servers running Python 2.5 or later due to changes in
           the way Python implements exceptions.
        
        ZODB ZEO clients from ZODB 3.2 on can talk to ZODB 3.9 servers.  ZODB
        ZEO Clients can talk to ZODB 3.8 and 3.9 ZEO servers.
        
        Prerequisites
        =============
        
        You must have Python installed. If you're using a system Python
        install, make sure development support is installed too.
        
        You also need the transaction, zc.lockfile, ZConfig, zdaemon,
        zope.event, zope.interface, zope.proxy and zope.testing packages.  If
        you don't have them and you can connect to the Python Package Index,
        then these will be installed for you if you don't have them.
        
        Installation
        ============
        
        ZODB is released as a distutils package.  The easiest ways to build
        and install it are to use `easy_install
        <http://peak.telecommunity.com/DevCenter/EasyInstall>`_, or
        `zc.buildout <http://www.python.org/pypi/zc.buildout>`_.
        
        To install by hand, first install the dependencies, ZConfig, zdaemon,
        zope.interface, zope.proxy and zope.testing.  These can be found
        in the `Python Package Index <http://www.python.org/pypi>`_.
        
        To run the tests, use the test setup command::
        
          python setup.py test
        
        It will download dependencies if needed.  If this happens, ou may get
        an import error when the test command gets to looking for tests.  Try
        running the test command a second time and you should see the tests
        run.
        
        ::
        
          python setup.py test
        
        To install, use the install command::
        
          python setup.py install
        
        
        Testing for Developers
        ======================
        
        The ZODB checkouts are `buildouts <http://www.python.org/pypi/zc.buildout>`_.
        When working from a ZODB checkout, first run the bootstrap.py script
        to initialize the buildout:
        
            % python bootstrap.py
        
        and then use the buildout script to build ZODB and gather the dependencies:
        
            % bin/buildout
        
        This creates a test script:
        
            % bin/test -v
        
        This command will run all the tests, printing a single dot for each
        test.  When it finishes, it will print a test summary.  The exact
        number of tests can vary depending on platform and available
        third-party libraries.::
        
            Ran 1182 tests in 241.269s
        
            OK
        
        The test script has many more options.  Use the ``-h`` or ``--help``
        options to see a file list of options.  The default test suite omits
        several tests that depend on third-party software or that take a long
        time to run.  To run all the available tests use the ``--all`` option.
        Running all the tests takes much longer.::
        
            Ran 1561 tests in 1461.557s
        
            OK
        
        
        Maintenance scripts
        -------------------
        
        Several scripts are provided with the ZODB and can help for analyzing,
        debugging, checking for consistency, summarizing content, reporting space used
        by objects, doing backups, artificial load testing, etc.
        Look at the ZODB/script directory for more informations.
        
        
        History
        =======
        
        The historical version numbering schemes for ZODB and ZEO are complicated.
        Starting with ZODB 3.4, the ZODB and ZEO version numbers are the same.
        
        In the ZODB 3.1 through 3.3 lines, the ZEO version number was "one smaller"
        than the ZODB version number; e.g., ZODB 3.2.7 included ZEO 2.2.7.  ZODB and
        ZEO were distinct releases prior to ZODB 3.1, and had independent version
        numbers.
        
        Historically, ZODB was distributed as a part of the Zope application
        server.  Jim Fulton's paper at the Python conference in 2000 described
        a version of ZODB he called ZODB 3, based on an earlier persistent
        object system called BoboPOS.  The earliest versions of ZODB 3 were
        released with Zope 2.0.
        
        Andrew Kuchling extracted ZODB from Zope 2.4.1 and packaged it for
        use by standalone Python programs.  He called this version
        "StandaloneZODB".  Andrew's guide to using ZODB is included in the Doc
        directory.  This version of ZODB was hosted at
        http://sf.net/projects/zodb.  It supported Python 1.5.2, and might
        still be of interest to users of this very old Python version.
        
        Zope Corporation released a version of ZODB called "StandaloneZODB
        1.0" in Feb. 2002.  This release was based on Andrew's packaging, but
        built from the same CVS repository as Zope.  It is roughly equivalent
        to the ZODB in Zope 2.5.
        
        Why not call the current release StandaloneZODB?  The name
        StandaloneZODB is a bit of a mouthful.  The standalone part of the
        name suggests that the Zope version is the real version and that this
        is an afterthought, which isn't the case.  So we're calling this
        release "ZODB". We also worked on a ZODB4 package for a while and
        made a couple of alpha releases.  We've now abandoned that effort,
        because we didn't have the resources to pursue ot while also maintaining
        ZODB(3).
        
        License
        =======
        
        ZODB is distributed under the Zope Public License, an OSI-approved
        open source license.  Please see the LICENSE.txt file for terms and
        conditions.
        
        The ZODB/ZEO Programming Guide included in the documentation is a
        modified version of Andrew Kuchling's original guide, provided under
        the terms of the GNU Free Documentation License.
        
        
        More information
        ================
        
        We maintain a Wiki page about all things ZODB, including status on
        future directions for ZODB.  Please see
        
            http://wiki.zope.org/ZODB/FrontPage
        
        and feel free to contribute your comments.  There is a Mailman mailing
        list in place to discuss all issues related to ZODB.  You can send
        questions to
        
            zodb-dev@zope.org
        
        or subscribe at
        
            http://lists.zope.org/mailman/listinfo/zodb-dev
        
        and view its archives at
        
            http://lists.zope.org/pipermail/zodb-dev
        
        Note that Zope Corp mailing lists have a subscriber-only posting policy.
        
        Andrew's ZODB Programmers Guide is made available in several
        forms, including DVI and HTML.  To view it online, point your
        browser at the file Doc/guide/zodb/index.html
        
        
        Bugs and Patches
        ================
        
        Bug reports and patches should be added to the Launchpad:
        
            https://launchpad.net/zodb
        
        
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        ================
         Change History
        ================
        
        3.9.7 (2010-09-28)
        ==================
        
        Bugs Fixed
        ----------
        
        - Changes in way that garbage collection treats dictionaries in Python
          2.7 broke the object/connection cache implementation.
          (https://bugs.launchpad.net/zodb/+bug/641481)
        
          Python 2.7 wasn't officially supported, but we were releasing
          binaries for it, so ...
        
        - Logrotation/repoening via a SIGUSR2 signal wasn't implemented.
          (https://bugs.launchpad.net/zodb/+bug/143600)
        
        - When using multi-databases, cache-management operations on a
          connection, cacheMinimize and cacheGC, weren't applied to
          subconnections.
        
        3.9.6 (2010-09-21)
        ==================
        
        Bugs Fixed
        ----------
        
        - Updating blobs in save points could cause spurious "invalidations
          out of order" errors.  https://bugs.launchpad.net/zodb/+bug/509801
        
          (Thanks to Christian Zagrodnick for chasing this down.)
        
        - If a ZEO client process was restarted while invalidating a ZEO cache
          entry, the cache could be left in a stage when there is data marked
          current that should be invalidated, leading to persistent conflict
          errors.
        
        - Corrupted or invalid cache files prevented ZEO clients from
          starting. Now, bad cache files are moved aside.
        
        - Invalidations of object records in ZEO caches, where the
          invalidation transaction ids matched the cached transaction ids
          should have been ignored.
        
        - Shutting down a process while committing a transaction or processing
          invalidations from the server could cause ZEO persistent client
          caches to have invalid data.  This, in turn caused stale data to
          remain in the cache until it was updated.
        
        - Conflict errors didn't invalidate ZEO cache entries.
        
        - When objects were added in savepoints and either the savepoint was
          rolled back (https://bugs.launchpad.net/zodb/+bug/143560) or the
          transaction was aborted
          (https://mail.zope.org/pipermail/zodb-dev/2010-June/013488.html)
          The objects' _p_oid and _p_jar variables weren't cleared, leading to
          surprizing errors.
        
        - Objects added in transactions that were later aborted could have
          _p_changed still set (https://bugs.launchpad.net/zodb/+bug/615758).
        
        - ZEO extension methods failed when a client reconnected to a
          storage. (https://bugs.launchpad.net/zodb/+bug/143344)
        
        - On Mac OS X, clients that connected and disconnected quickly could
          cause a ZEO server to stop accepting connections, due to a failure
          to catch errors in the initial part of the connection process.
        
          The failure to properly handle exceptions while accepting
          connections is potentially problematic on other platforms.
        
          Fixes: https://bugs.launchpad.net/zodb/+bug/135108
        
        - Passing keys or values outside the range of 32-bit ints on 64-bit
          platforms led to undetected overflow errors. Now these cases cause
          Type errors to be raised.
        
          https://bugs.launchpad.net/zodb/+bug/143237
        
        - BTree sets and tree sets didn't correctly check values passed to
          update or to constructors, causing Python to exit under certain
          circumstances.
        
        - The verbose mode of the fstest was broken.
          (https://bugs.launchpad.net/zodb/+bug/475996)
        
        3.9.5 (2010-04-23)
        ==================
        
        Bugs Fixed
        ----------
        
        - Fixed bug in cPickleCache's byte size estimation logic.
          (https://bugs.launchpad.net/zodb/+bug/533015)
        
        - Fixed a serious bug that caused cache failures when run
          with Python optimization turned on.
        
          https://bugs.launchpad.net/zodb/+bug/544305
        
        - Fixed a bug that caused savepoint rollback to not properly
          set object state when objects implemented _p_invalidate methods
          that reloaded ther state (unghostifiable objects).
        
          https://bugs.launchpad.net/zodb/+bug/428039
        
        - cross-database wekrefs weren't handled correctly.
        
          https://bugs.launchpad.net/zodb/+bug/435547
        
        - The mkzeoinst script was fixed to tell people to
          install and use the mkzeoinstance script. :)
        
        3.9.4 (2009-12-14)
        ==================
        
        Bugs Fixed
        ----------
        
        - A ZEO threading bug could cause transactions to read inconsistent
          data.  (This sometimes caused an AssertionError in
          Connection._setstate_noncurrent.)
        
        - DemoStorage.loadBefore sometimes returned invalid data which
          would trigger AssertionErrors in ZODB.Connection.
        
        - History support was broken when using stprages that work with ZODB
          3.8 and 3.9.
        
        - zope.testing was an unnecessary non-testing dependency.
        
        - Internal ZEO errors were logged at the INFO level, rather
          than at the error level.
        
        - The FileStorage backup and restore script, repozo, gave a
          deprecation warning under Python 2.6.
        
        - C Header files weren't installed correctly.
        
        3.9.3 (2009-10-23)
        ==================
        
        Bugs Fixed
        ----------
        
        - 2 BTree bugs, introduced by a bug fix in 3.9.0c2, sometimes caused
          deletion of keys to be improperly handled, resulting in data being
          available via iteraation but not item access.
        
        3.9.2 (2009-10-13)
        ==================
        
        Bugs Fixed
        ----------
        
        - ZEO manages a separate thread for client network IO.  It created
          this thread on import, which caused problems for applications that
          implemented daemon behavior by forking.  Now, the client thread
          isn't created until needed.
        
        - File-storage pack clean-up tasks that can take a long time
          unnecessarily blocked other activity.
        
        - In certain rare situations, ZEO client connections would hand during
          the initial connection setup.
        
        3.9.1 (2009-10-01)
        ==================
        
        Bugs Fixed
        ----------
        
        - Conflict errors committing blobs caused ZEO servers to stop committing
          transactuions.
        
        3.9.0 (2009-09-08)
        ==================
        
        New Features (in more or less reverse chronological order)
        ----------------------------------------------------------
        
        - The Database class now has an ``xrefs`` keyword argument and a
          corresponding allow-implicit-cross-references configuration option.
          which default to true.  When set to false, cross-database references
          are disallowed.
        
        - Added support for RelStorage.
        
        - As a convenience, the connection root method for returning the root
          object can now *also* be used as an object with attributes mapped to
          the root-object keys.
        
        - Databases have a new method, ``transaction``, that can be used with the
          Python (2.5 and later) ``with`` statement::
        
             db = ZODB.DB(...)
             with db.transaction() as conn:
                  # ... do stuff with conn
        
          This uses a private transaction manager for the connection.
          If control exits the block without an error, the transaction is
          committed, otherwise, it is aborted.
        
        - Convenience functions ZODB.connection and ZEO.connection provide a
          convenient way to open a connection to a database.  They open a
          database and return a connection to it. When the connection is
          closed, the database is closed as well.
        
        - The ZODB.config databaseFrom... methods now support
          multi-databases. If multiple zodb sections are used to define
          multiple databases, the databases are connected in a multi-database
          arrangement and the first of the defined databases is returned.
        
        - The zeopack script has gotten a number of improvements:
        
          - Simplified command-line interface. (The old interface is still
            supported, except that support for ZEO version 1 servers has been
            dropped.)
        
          - Multiple storages can be packed in sequence.
        
            - This simplifies pack scheduling on servers serving multiple
              databases.
        
            - All storages are packed to the same time.
        
          - You can now specify a time of day to pack to.
        
          - The script will now time out if it can't connect to s storage in
            60 seconds.
        
        - The connection now estimates the object size based on its pickle size
          and informs the cache about size changes.
        
          The database got additional configurations options (`cache-size-bytes`
          and `historical-cache-size-bytes`) to limit the
          cache size based on the estimated total size of cached objects.
          The default values are 0 which has the interpretation "do not limit
          based on the total estimated size".
          There are corresponding methods to read and set the new configuration
          parameters.
        
        - Connections now have a public ``opened`` attribute that is true when
          the connection is open, and false otherwise.  When true, it is the
          seconds since the epoch (time.time()) when the connection was
          opened. This is a renaming of the previous ``_opened`` private
          variable.
        
        - FileStorage now supports blobs directly.
        
        - You can now control whether FileStorages keep .old files when packing.
        
        - POSKeyErrors are no longer logged by ZEO servers, because they are
          really client errors.
        
        - A new storage interface, IExternalGC, to support external garbage
          collection, http://wiki.zope.org/ZODB/ExternalGC, has been defined
          and implemented for FileStorage and ClientStorage.
        
        - As a small convenience (mainly for tests), you can now specify
          initial data as a string argument to the Blob constructor.
        
        - ZEO Servers now provide an option, invalidation-age, that allows
          quick verification of ZEO clients have been disconnected for less
          than a given time even if the number of transactions the client
          hasn't seen exceeds the invalidation queue size. This is only
          recommended if the storage being served supports efficient iteration
          from a point near the end of the transaction history.
        
        - The FileStorage iterator now handles large files better.  When
          iterating from a starting transaction near the end of the file, the
          iterator will scan backward from the end of the file to find the
          starting point.  This enhancement makes it practical to take
          advantage of the new storage server invalidation-age option.
        
        - Previously, database connections were managed as a stack.  This
          tended to cause the same connection(s) to be used over and over.
          For example, the most used connection would typically be the only
          connection used.  In some rare situations, extra connections could
          be opened and end up on the top of the stack, causing extreme memory
          wastage.  Now, when connections are placed on the stack, they sink
          below existing connections that have more active objects.
        
        - There is a new pool-timeout database configuration option to specify that
          connections unused after the given time interval should be garbage
          collection.  This will provide a means of dealing with extra
          connections that are created in rare circumstances and that would
          consume an unreasonable amount of memory.
        
        - The Blob open method now supports a new mode, 'c', to open committed
          data for reading as an ordinary file, rather than as a blob file.
          The ordinary file may be used outside the current transaction and
          even after the blob's database connection has been closed.
        
        - ClientStorage now provides blob cache management. When using
          non-shared blob directories, you can set a target cache size and the
          cache will periodically be reduced try to keep it below the target size.
        
          The client blob directory layout has changed.  If you have existing
          non-shared blob directories, you will have to remove them.
        
        - ZODB 3.9 ZEO clients can connect to ZODB 3.8 servers.  ZODB ZEO clients
          from ZODB 3.2 on can connect to ZODB 3.9 servers.
        
        - When a ZEO cache is stale and would need verification, a
          ZEO.interfaces.StaleCache event is published (to zope.event).
          Applications may handle this event and take action such as exiting
          the application without verifying the cache or starting cold.
        
        - There's a new convenience function, ZEO.DB, for creating databases
          using ZEO Client Storages.  Just call ZEO.DB with the same arguments
          you would otherwise pass to ZEO.ClientStorage.ClientStorage::
        
            import ZEO
            db = ZEO.DB(('some_host', 8200))
        
        - Object saves are a little faster
        
        - When configuring storages in a storage server, the storage name now
          defaults to "1".  In the overwhelmingly common case that a single
          storage, the name can now be omitted.
        
        - FileStorage now provides optional garbage collection.  A 'gc'
          keyword option can be passed to the pack method.  A false value
          prevents garbage collection.
        
        - The FileStorage constructor now provides a boolean pack_gc option,
          which defaults to True, to control whether garbage collection is
          performed when packing by default. This can be overridden with the
          gc option to the pack method.
        
          The ZConfig configuration for FileStorage now includes a pack-gc
          option, corresponding to the pack_gc constructor argument.
        
        - The FileStorage constructor now has a packer keyword argument that
          allows an alternative packer to be supplied.
        
          The ZConfig configuration for FileStorage now includes a packer
          option, corresponding to the packer constructor argument.
        
        - MappingStorage now supports multi-version concurrency control and
          iteration and provides a better storage implementation example.
        
        - DemoStorage has a number of new features:
        
          - The ability to use a separate storage, such as a file storage to
            store changes
        
          - Blob support
        
          - Multi-version concurrency control and iteration
        
          - Explicit support for demo-storage stacking via push and pop methods.
        
        - Wen calling ZODB.DB to create a database, you can now pass a file
          name, rather than a storage to use a file storage.
        
        - Added support for copying and recovery of blob storages:
        
          - Added a helper function, ZODB.blob.is_blob_record for testing whether
            a data record is for a blob.  This can be used when iterating over a
            storage to detect blob records so that blob data can be copied.
        
            In the future, we may want to build this into a blob-aware
            iteration interface, so that records get blob file attributes
            automatically.
        
          - Added the IBlobStorageRestoreable interfaces for blob storages
            that support recovery via a restoreBlob method.
        
          - Updated ZODB.blob.BlobStorage to implement
            IBlobStorageRestoreable and to have a copyTransactionsFrom method
            that also copies blob data.
        
        - New `ClientStorage` configuration option `drop_cache_rather_verify`.
          If this option is true then the ZEO client cache is dropped instead of
          the long (unoptimized) verification. For large caches, setting this
          option can avoid effective down times in the order of hours when
          the connection to the ZEO server was interrupted for a longer time.
        
        - Cleaned-up the storage iteration API and provided an iterator implementation
          for ZEO.
        
        - Versions are no-longer supported.
        
        - Document conflict resolution (see ZODB/ConflictResolution.txt).
        
        - Support multi-database references in conflict resolution.
        
        - Make it possible to examine oid and (in some situations) database
          name of persistent object references during conflict resolution.
        
        - Moved the 'transaction' module out of ZODB.
          ZODB depends upon this module, but it must be installed separately.
        
        - ZODB installation now requires setuptools.
        
        - Added `offset` information to output of `fstail`
          script. Added test harness for this script.
        
        - Added support for read-only, historical connections based
          on datetimes or serials (TIDs).  See
          src/ZODB/historical_connections.txt.
        
        - Removed the ThreadedAsync module.
        
        - Now depend on zc.lockfile
        
        Bugs Fixed
        ----------
        
        - CVE-2009-2701: Fixed a vulnerability in ZEO storage servers when
          blobs are available. Someone with write access to a ZEO server
          configured to support blobs could read any file on the system
          readable by the server process and remove any file removable by the
          server process.
        
        - BTrees (and TreeSets) kept references to internal keys.
          https://bugs.launchpad.net/zope3/+bug/294788
        
        - BTree Sets and TreeSets don't support the standard set add method.
          (Now either add or the original insert method can be used to add an
          object to a BTree-based set.)
        
        - The runzeo script didn't work without a configuration file.
          (https://bugs.launchpad.net/zodb/+bug/410571)
        
        - Officially deprecated PersistentDict
          (https://bugs.launchpad.net/zodb/+bug/400775)
        
        - Calling __setstate__ on a persistent object could under certain
          uncommon cause the process to crash.
          (https://bugs.launchpad.net/zodb/+bug/262158)
        
        - When committing transactions involving blobs to ClientStorages with
          non-shared blob directories, a failure could occur in tpc_finish if
          there was insufficient disk space to copy the blob file or if the
          file wasn't available.  https://bugs.launchpad.net/zodb/+bug/224169
        
        - Savepoint blob data wasn't properly isolated. If multiple
          simultaneous savepoints in separate transactions modified the same
          blob, data from one savepoint would overwrite data for another.
        
        - Savepoint blob data wasn't cleaned up after a transaction abort.
          https://bugs.launchpad.net/zodb/+bug/323067
        
        - Opening a blob with modes 'r+' or 'a' would fail when the blob had no
          committed changes.
        
        - PersistentList's sort method did not allow passing of keyword parameters.
          Changed its sort parameter list to match that of its (Python 2.4+)
          UserList base class.
        
        - Certain ZEO server errors could cause a client to get into a state
          where it couldn't commit transactions.
          https://bugs.launchpad.net/zodb/+bug/374737
        
        - Fixed vulnerabilities in the ZEO network protocol that allow:
        
          - CVE-2009-0668 Arbitrary Python code execution in ZODB ZEO storage servers
          - CVE-2009-0669 Authentication bypass in ZODB ZEO storage servers
        
          The vulnerabilities only apply if you are using ZEO to share a
          database among multiple applications or application instances and if
          untrusted clients are able to connect to your ZEO servers.
        
        - Fixed the setup test command.  It previously depended on private
          functions in zope.testing.testrunner that don't exist any more.
        
        - ZEO client threads were unnamed, making it hard to debug thread
          management.
        
        - ZEO protocol 2 support was broken.  This caused very old clients to
          be unable to use new servers.
        
        - zeopack was less flexible than it was before.  -h should default to
          local host.
        
        - The "lawn" layout was being selected by default if the root of
          the blob directory happened to contain a hidden file or directory
          such as ".svn".  Now hidden files and directories are ignored
          when choosing the default layout.
        
        - BlobStorage was not compatible with MVCC storages because the
          wrappers were being removed by each database connection.  Fixed.
        
        - Saving indexes for large file storages failed (with the error:
          RuntimeError: maximum recursion depth exceeded).  This can cause a
          FileStorage to fail to start because it gets an error trying to save
          its index.
        
        - Sizes of new objects weren't added to the object cache size
          estimation, causing the object-cache size limiting feature to let
          the cache grow too large when many objects were added.
        
        - Deleted records weren't removed when packing file storages.
        
        - Fixed analyze.py and added test.
        
        - fixed Python 2.6 compatibility issue with ZEO/zeoserverlog.py
        
        - using hashlib.sha1 if available in order to avoid DeprecationWarning
          under Python 2.6
        
        - made runzeo -h work
        
        - The monitor server didn't correctly report the actual number of
          clients.
        
        - Packing could return spurious errors due to errors notifying
          disconnected clients of new database size statistics.
        
        - Undo sometimes failed for FileStorages configured to support blobs.
        
        - Starting ClientStorages sometimes failed with non-new but empty
          cache files.
        
        - The history method on ZEO clients failed.
        
        - Fix for bug #251037: Make packing of blob storages non-blocking.
        
        - Fix for bug #220856: Completed implementation of ZEO authentication.
        
        - Fix for bug #184057: Make initialisation of small ZEO client file cache
          sizes not fail.
        
        - Fix for bug #184054: MappingStorage used to raise a KeyError during `load`
          instead of a POSKeyError.
        
        - Fixed bug in Connection.TmpStore: load() would not defer to the backend
          storage for loading blobs.
        
        - Fix for bug #181712: Make ClientStorage update `lastTransaction` directly
          after connecting to a server, even when no cache verification is necessary.
        
        - Fixed bug in blob filesystem helper: the `isSecure` check was inverted.
        
        - Fixed bug in transaction buffer: a tuple was unpacked incorrectly in
          `clear`.
        
        - Bugfix the situation in which comparing persistent objects (for
          instance, as members in BTree set or keys of BTree) might cause data
          inconsistency during conflict resolution.
        
        - Fixed bug 153316: persistent and BTrees were using `int`
          for memory sizes which caused errors on x86_64 Intel Xeon machines
          (using 64-bit Linux).
        
        - Fixed small bug that the Connection.isReadOnly method didn't
          work after a savepoint.
        
        - Bug #98275: Made ZEO cache more tolerant when invalidating current
          versions of objects.
        
        - Fixed a serious bug that could cause client I/O to stop
          (hang). This was accompanied by a critical log message along the
          lines of: "RuntimeError: dictionary changed size during iteration".
        
        - Fixed bug #127182: Blobs were subclassable which was not desired.
        
        - Fixed bug #126007: tpc_abort had untested code path that was
          broken.
        
        - Fixed bug #129921: getSize() function in BlobStorage could not
          deal with garbage files
        
        - Fixed bug in which MVCC would not work for blobs.
        
        - Fixed bug in ClientCache that occurred with objects larger than the total
          cache size.
        
        - When an error occured attempting to lock a file and logging of said error was
          enabled.
        
        - FileStorages previously saved indexes after a certain
          number of writes.  This was done during the last phase of two-phase
          commit, which made this critical phase more subject to errors than
          it should have been.  Also, for large databases, saves were done so
          infrequently as to be useless.  The feature was removed to reduce
          the chance for errors during the last phase of two-phase commit.
        
        - File storages previously kept an internal object id to
          transaction id mapping as an optimization. This mapping caused
          excessive memory usage and failures during the last phase of
          two-phase commit. This optimization has been removed.
        
        - Refactored handling of invalidations on ZEO clients to fix
          a possible ordering problem for invalidation messages.
        
        - On many systems, it was impossible to create more than 32K
          blobs. Added a new blob-directory layout to work around this
          limitation.
        
        - Fixed bug that could lead to memory errors due to the use
          of a Python dictionary for a mapping that can grow large.
        
        - Fixed bug #251037: Made packing of blob storages non-blocking.
        
        - Fixed a bug that could cause InvalidObjectReference errors
          for objects that were explicitly added to a database if the object
          was modified after a savepoint that added the object.
        
        - Fixed several bugs that caused ZEO cache corruption when connecting
          to servers. These bugs affected both persistent and non-persistent caches.
        
        - Improved the the ZEO client shutdown support to try to
          avoid spurious errors on exit, especially for scripts, such as zeopack.
        
        - Packing failed for databases containing cross-database references.
        
        - Cross-database references to databases with empty names
          weren't constructed properly.
        
        - The zeo client cache used an excessive amount of memory, causing applications
          with large caches to exhaust available memory.
        
        - Fixed a number of bugs in the handling of persistent ZEO caches:
        
          - Cache records are written in several steps.  If a process exits
            after writing begins and before it is finishes, the cache will be
            corrupt on restart.  The way records are written was changed to
            make cache record updates atomic.
        
          - There was no lock file to prevent opening a cache multiple times
            at once, which would lead to corruption.  Persistent caches now
            use lock files, in the same way that file storages do.
        
          - A bug in the cache-opening logic led to cache failure in the
            unlikely event that a cache has no free blocks.
        
        - When using ZEO Client Storages, Errors occured when trying to store
          objects too big to fit in the ZEO cache file.
        
        - Fixed bug in blob filesystem helper: the `isSecure` check was inverted.
        
        - Fixed bug in transaction buffer: a tuple was unpacked incorrectly in
          `clear`.
        
        - Fixed bug in Connection.TmpStore: load() would not defer to the
          back-end storage for loading blobs.
        
        - Fixed bug #190884: Wrong reference to `POSKeyError` caused NameError.
        
        - Completed implementation of ZEO authentication. This fixes issue 220856.
        
Platform: any
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: Zope Public License
Classifier: Programming Language :: Python
Classifier: Topic :: Database
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Classifier: Operating System :: Microsoft :: Windows
Classifier: Operating System :: Unix
