================
Change History
================
3.9.0 (2008-??-??)
====================
New Features
------------
- 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.
XXX There are known issues with this implementation that need to be
sorted out before it is "released".
3.9.0a7 (2008-12-??)
====================
New Features
------------
- 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 to the target size.
The client blob directory layout has changed. If you have existing
non-shared blob directories, you will have to remove them.
Bugs Fixed
----------
- Starting ClientStorages sometimes failed with non-new but empty
cache files.
3.9.0a6 (2008-11-30)
====================
New Features
------------
- ZODB 3.9 ZEO clients can connect to ZODB 3.8 servers.
Bug Fixes
---------
- ZODB 3.8 clients couldn't talk to ZODB 3.9 servers.
- The history method on ZEO clients failed.
3.9.0a5 (2008-11-21)
====================
New Features
------------
- 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
- The previous (ZODB 3.8) ZEO client-cache format is supported.
The newer cache format introduced in ZODB 3.9.0a1 is no-longer
supported. Cache files can still be larger than 4G. Cache file
sizes can now be changed.
- 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 ommitted.
Bug Fixes
---------
- ZEO client transaction iterators weren't properly handled after on
disconnects.
- The code to drop a ZEO client cache rather than verifying didn't
drop it and didn't leave the client storage in a valid state.
3.9.0a4 (2008-11-06)
====================
Bug Fixes
---------
- DemoStorage could sometimes hand out the same new object id more
than once.
3.9.0a3 (2008-11-04)
====================
New Features
------------
- 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.
Bug Fixes
---------
- DemoStorage could sometimes hand out the same new object id more
than once.
3.9.0a2 (2008-10-31)
====================
Bug Fixes
---------
- MappingStorage hung when committing a transaction *after* committing
an empty transaction.
3.9.0a1 (2008-10-29)
====================
New Features
------------
- 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 dfor 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 downtimes 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.
- ZEO cache files can be larger than 4G. Note that older ZEO cache
files are not supported.
- Document conflict resolution (see ZODB/ConflictResolution.txt).
- Support multidatabase references in conflict resolution.
- Make it possible to examine oid and (in some situations) database
name of persistent object references during conflict resolution.
- Moved '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
----------
- 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 inversed.
- 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 accomonied 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.
3.8.1b9 (2008-??-??)
====================
Bugs Fixed:
- When an error occured attempting to lock a file and logging of said error was
enabled.
3.8.1b8 (2008-09-22
====================
Bugs Fixed:
- 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.
- An ZEO cache internal data structure can get out of sync
with the data in a way that prevents data from being loaded into the
cache. We don't yet know why, but added an exception handler to
prevent this error from being fatal.
- Fixed setup.py use of setuptools vs distutils, so .c and .h
files are included in the bdist_egg.
- On many systems, it was impossible to create more than 32K
blobs. Added a new blob-directory layout to work around this
limitation.
3.8.1b7 (2008-08-23)
====================
Bugs Fixed:
- Fixed a bug, introduced in an earlier beta, that allowed
clients to connect to out of date servers.
- 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.
3.8.1b6 (2008-07-24)
====================
Bugs Fixed:
- 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.
3.8.1b5 (2008-07-14)
====================
Bugs Fixed:
- 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.
3.8.1b4 (2008-05-23)
====================
Bugs Fixed:
- Packing failed for databases containing cross-database references.
3.8.1b3 (2008-05-14)
====================
Bugs Fixed:
- Cross-database references to databases with empty names
weren't constructed properly.
3.8.1b2 (2008-05-13)
====================
Bugs Fixed:
- The cache used an excessive amount of memory, causing applications
with large caches to exhaust available memory.
3.8.1b1 (2008-05-08)
====================
Bugs Fixed:
- 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 writted 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 inversed.
- Fixed bug in transaction buffer: a tuple was unpacked incorrectly in
`clear`.
- Fixed bug in Connection.TmpStore: load() would not defer to the
backend storage for loading blobs.
- Fixed bug #190884: Wrong reference to `POSKeyError` caused NameError.
- Completed implementation of ZEO authentication. This fixes issue 220856.