Hello Lucene users,

On behalf of the Lucene dev community (a growing community far larger than just the committers) I would like to announce the release of Lucene 2.9.

While we generally try and maintain full backwards compatibility between major versions, Lucene 2.9 has a variety of breaks that are spelled out in the ‘Changes in backwards compatibility policy’ section of CHANGES.txt.

We recommend that you recompile your application with Lucene 2.9 rather than attempting to “drop” it in. This will alert you to any issues you may have to fix if you are affected by one of the backward compatibility breaks. As always, its a really good idea to thoroughly read CHANGES.txt before upgrading.

Lucene 2.9 comes with a bevy of new features, including:

  • Per segment searching and caching (can lead to much faster reopen among other things)
  • Near real-time search capabilities added to IndexWriter
  • New Query types
  • Smarter, more scalable multi-term queries (wildcard, range, etc)
  • A freshly optimized Collector/Scorer API
  • Improved Unicode support and the addition of Collation contrib
  • A new Attribute based TokenStream API
  • A new QueryParser framework in contrib with a core QueryParser replacement impl included.
  • Scoring is now optional when sorting by Field, or using a custom Collector, gaining sizable performance when scores are not required.
  • New analyzers (PersianAnalyzer, ArabicAnalyzer, SmartChineseAnalyzer)
  • New fast-vector-highlighter for large documents
  • Lucene now includes high-performance handling of numeric fields. Such fields are indexed with a trie structure, enabling simple to use and much faster numeric range searching without having to externally pre-process numeric values into textual values.


And many, many more features, bug fixes, optimizations, and variousimprovements. You can find the full list of changes here:
http://lucene.apache.org/java/2_9_0/changes/Changes.html

Many changes have also occurred in Lucene’s Contrib area:
http://lucene.apache.org/java/2_9_0/changes/Contrib-Changes.html

Binary and source distributions are available at http://www.apache.org/dyn/closer.cgi/lucene/java/

Lucene artifacts are also available in the Maven2 repository at
http://repo1.maven.org/maven2/org/apache/lucene/

The Next Release

The next release will be Lucene 3.0. This should come along shortly, and will remove all of the deprecated code in Lucene 2.9. Lucene 3.0 will also be the first release to move from Java 1.4 to Java 1.5 as a requirement.

Thanks,
Mark Miller