June 2011, Apache Lucene™ 3.2 available
The Lucene PMC is pleased to announce the release of Apache Lucene 3.2.
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:
http://www.apache.org/dyn/closer.cgi/lucene/java (see note below).
See the CHANGES.txt file included with the release for a full list of details.
Lucene 3.2 Release Highlights
* A new grouping module, under lucene/contrib/grouping, enables
search results to be grouped by a single-valued indexed field.
* A new IndexUpgrader tool fully converts an old index to the
* A new Directory implementation, NRTCachingDirectory, caches small
segments in RAM, to reduce the I/O load for applications with fast
NRT reopen rates.
* A new Collector implementation, CachingCollector, is able to
gather search hits (document IDs and optionally also scores) and
then replay them. This is useful for Collectors that require two
or more passes to produce results.
* Index a document block using IndexWriter's new addDocuments or
updateDocuments methods. These experimental APIs ensure that the
block of documents will forever remain contiguous in the index,
enabling interesting future features like grouping and joins.
* A new default merge policy, TieredMergePolicy, which is more
efficient due to being able to merge non-contiguous segments.
See http://s.apache.org/merging for details.
* NumericField is now returned correctly when you load a stored
document (previously you received a normal Field back, with the
numeric value converted string).
* Deleted terms are now applied during flushing to the newly flushed
segment, which is more efficient than having to later initialize a
reader for that segment.
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