Berkeley DB Java Edition
Release Notes

2.1.30, January 25, 2006

These release notes contain:

• Overview
• New in this Release

Overview

Berkeley DB Java Edition (JE) is a 100% pure Java implementation of Berkeley DB. It implements a transactional store model based on a B+Tree access method.

JE's capabilities and features are described in the Getting Started with Berkeley DB Java Edition guide. That document also introduces the JE API set. For a complete description of the JE API set, see the Javadoc. For a description of how to use JE and the Sleepycat Java Collections API, see the collections tutorial. For an overview on using transactions, see Writing Transactional Applications with Berkeley DB, Java Edition

New in this Release

This is release 2.1.30 of Berkeley DB Java Edition, and the fifth release in the JE 2.0 line. Key changes since version JE 2.0.90 are described below; the complete list of changes can be found in the change log page for this release.

Note: If you are using Mac OS X, please be aware of the following issue. Java version 1.4.2 on Mac OS X reports the wrong value for Runtime.maxMemory. JE calculates the default cache size as a percentage of maxMemory.  Because of this, for Java 1.4.2 on Mac OS X only, JE will assume that the Java maxMemory value is 64 MB.  With the default je.maxMemoryPercent configuration parameter (60%) the default JE cache size will be approximately 38 MB.  This default is fixed -- it does not change if the Java memory size is different than 64 MB.  To specify a different JE cache size, you must explicitly set the je.maxMemory configuration property.  The je.maxMemory property can be specified in the je.properties file or by calling EnvironmentConfig.setCacheSize.

New Features:

1. Multi-key secondary databases are now supported, providing direct support for many-to-many and one-to-many relationships. See com.sleepycat.je.SecondaryMultiKeyCreator, com.sleepycat.je.ForeignMultiKeyNullifier and examples/je/ToManyExample.java. [#13842]

General Environment Changes:

A key focus of this release is improved performance, particularly for multithreaded use cases. A few examples are:

• Multithreaded concurrency has benefited from changes which recognize and take advantage of the presence of a Java 1.5 JVM.
• The implementation has been modified and tuned to reduce contention on some internal data structures.
• There are new user options like non-locking mode and control over the number of lock tables that provide customization for more scenarios.
• A variety of operations like Database.preload() and Environment.truncateDatabase are orders of magnitude faster because they use new algorithm to sort and optimize I/O.

This release also contains a variety of bug fixes. The change log contains the complete and detailed description of all changes.

Documentation Changes:

A new documentation guide, "Writing Transactional Applications with Berkeley DB, Java Edition" is now available both in the distribution and through the Sleepycat Developer Zone. The Developer Zone is also the home of the new JE FAQ section, which has updated and expanded topics.

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