March 2013, Apache Lucene™ 4.2 available
The Lucene PMC is pleased to announce the release of Apache Lucene 4.2
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
Lucene 4.2 Release Highlights:
* Lucene 4.2 has a new default codec (Lucene42Codec) with a more
efficient docvalues format (sorted bytes in FST, less addressing
overhead, improved numeric compression) and smaller term
vectors (LZ4-compressed terms dictionaries and payloads, delta-encoded
positions and offsets using blocks of packed integers).
* Doc values external and codec API and implementations have been
simplified: the codec is no longer responsible for buffering doc
values; the numerous types have been consolidated down to only
three (NUMERIC, BINARY, SORTED); PerFieldDocValuesFormat lets you
set a different format for each field, and the doc values and FieldCache
APIs were unified.
* Significant refactoring and performance enhancements to the facet
module, resulting in overall ~3.8X speedup in one case (single Date
* DrillDownQuery in the facet module now supports multi-select.
* A new DrillSideways class enables counting facet labels and counts
for both hits and near-misses in a single query. See
* An additional docvalues type (SORTED_SET) was added that supports multiple
* FSTs are a bit smaller, and the FST package supports FSTs over 2GB
* A new LiveFieldValues class lets you get live or real-time values
for any indexed doc / field. See http://blog.mikemccandless.com/2013/01/getting-real-time-field-values-in-lucene.html
* Added a new classification module.
* Various bugfixes and optimizations since the 4.1 release.
Please read CHANGES.txt for a full list of new features.
Please report any feedback to the mailing lists
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