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From Robert Muir <>
Subject [ANNOUNCE] Apache Lucene 4.0-beta released.
Date Tue, 14 Aug 2012 11:35:02 GMT
14 August 2012, Apache Luceneā€š 4.0-beta available
The Lucene PMC is pleased to announce the release of Apache Lucene 4.0-beta

Apache Lucene is a high-performance, full-featured text search engine
library written entirely in Java. It is a technology suitable for nearly
any application that requires full-text search, especially cross-platform.

This release contains numerous bug fixes, optimizations, and
improvements, some of which are highlighted below.  The release
is available for immediate download at:

See the CHANGES.txt file included with the release for a full list of

Highlights of changes since 4.0-alpha:

  * IndexWriter.tryDeleteDocument can sometimes delete by document
    ID, for higher performance in some applications.

  * New experimental postings formats: BloomFilteringPostingsFormat uses
    a bloom filter to sometimes avoid disk seeks when looking up terms,
    DirectPostingsFormat holds all postings as simple byte[] and int[]
    for very fast performance at the cost of very high RAM consumption.

  * CJK analysis improvements: JapaneseIterationMarkCharFilter normalizes
    Japanese iteration marks, added unigram+bigram support to CJKBigramFilter.

  * Improvements to Scorer navigation API (Scorer.getChildren) to support
    all queries, useful for determining which portions of the query matched.

  * Analysis improvements: factories for creating Tokenizer, TokenFilter
    and CharFilter have been moved from Solr to Lucene's analysis module,
    less memory overhead for StandardTokenizer and Snowball filters.

  * Improved highlighting for multi-valued fields.

  * Various other API changes, optimizations and bug fixes.

Please read CHANGES.txt and MIGRATE.txt for a full list of new
features and notes on upgrading.
Particularly, the new apis are not compatible with previous version of
Lucene, however, file
format backwards compatibility is provided for indexes from the 3.0
series and the 4.0-alpha release.

This is a beta release for early adopters. The guarantee for this beta
release is that the index
format will be the 4.0 index format, supported through the 5.x series
of Apache Lucene, unless there
is a critical bug (e.g. that would cause index corruption) that would
prevent this.

Please report any feedback to the mailing lists

Happy searching,

Apache Lucene/Solr Developers

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