[Zope-Checkins] SVN: Zope/trunk/doc/WHATSNEW.rst Fill in the what's new section for the ZODB

Hanno Schlichting hannosch at hannosch.eu
Sat Jun 5 10:11:30 EDT 2010

Log message for revision 113141:
  Fill in the what's new section for the ZODB

  U   Zope/trunk/doc/WHATSNEW.rst

Modified: Zope/trunk/doc/WHATSNEW.rst
--- Zope/trunk/doc/WHATSNEW.rst	2010-06-05 13:35:54 UTC (rev 113140)
+++ Zope/trunk/doc/WHATSNEW.rst	2010-06-05 14:11:29 UTC (rev 113141)
@@ -11,9 +11,49 @@
 ZODB 3.10
+This version of Zope includes ZODB 3.10 - a new major version of the ZODB.
+Among the notable changes are a variety of performance improvements. The ZEO
+server process is now multi-threaded. If the underlying file system and disk
+storage can handle concurrent disk I/O efficiently a throughput increase by a
+factor of up to four has been seen. On a related note using solid state disks
+for the ZEO server has a similar effect and can increase throughput by the
+same factor. Both of these effects combined can lead to an increase of up to
+sixteen times the throughput in high load scenarios.
+File storage indexes use a new format, which is both smaller in size and can
+be read much faster. The repozo backup script now also backs up the index files
+in addition to the actual data, so in a restore scenario the index doesn't have
+to be recreated. For large databases this can bring down the total downtime in
+a restore scenario by a significant amount of time.
+The ZODB has added support for wrapper storages that transform pickle data.
+Applications for this include compression and encryption. A storage using
+standard zlib compression is available as a new package called
+`zc.zlibstorage <http://pypi.python.org/pypi/zc.zlibstorage>`_. In content
+management scenarios where strings constitute the most of the non-blob data,
+this can reduce the Data.fs size by a factor of two or more. The overhead of
+compressing and uncompressing is negligible. This saves both network I/O and
+disk space. More importantly the database has better chances of fitting into
+the operating systems disk cache and thus into memory. The second advantage is
+less important when using solid state disks.
+Databases now warn when committing very large records (> 16MB). This is to try
+to warn people of likely design mistakes. There is a new option
+(large_record_size/large-record-size) to control the record size at which the
+warning is issued. This should help developers to better understand the storage
+implications of their code, which has been rather transparent so far.
+The mkzeoinst script has been moved to a separate project
+`zope.mkzeoinstance <http://pypi.python.org/pypi/zope.mkzeoinstance>`_ and is
+no-longer included with ZODB. You will need to use this new package to set up
+ZEO servers or use the
+`plone.recipe.zeoserver <http://pypi.python.org/pypi/plone.recipe.zeoserver>`_
+recipe if you use `buildout <http://www.buildout.org/>`_.
+More information can be found in the detailed
+`change log <http://pypi.python.org/pypi/ZODB3/3.10.0b1.>`_.

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