?? July 2022, Apache Lucene™ 9.3 available

The Lucene PMC is pleased to announce the release of Apache Lucene 9.3

Apache Lucene is a high-performance, full-featured search engine library written entirely in Java. It is a technology suitable for nearly any application that requires structured search, full-text search, faceting, nearest-neighbor search on high-dimensionality vectors, spell correction or query suggestions.

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

https://lucene.apache.org/core/downloads.html

Lucene 9.3 Release Highlights

New features

• Merge on full flush is enabled now by default with a timeout of 500ms, giving the merge policy a chance to merge NRT segments together before publishing a new point-in-time view of the IndexReader. This should give queries a small performance boost in the near-realtime case, especially terms-dictionary-intensive queries like fuzzy queries.
• Add getAllChildren functionality to facets.
• Added facetsets module for high dimensional (hyper-rectangle) faceting. 

Optimizations

• Top-level two-clause disjunctions sorted by score now use the block-max MAXSCORE algorithm, which introduced a 40%-75% speedup in our benchmarks.
• BooleanQuery can return quick counts for simple boolean queries.

• When running KnnVectorQuery with a filter, reuse the cached filter bit set.

Other

• Update randomizedtesting to 2.8.0, hppc to 0.9.1, morfologik to 2.1.9.

... plus a number of helpful bug fixes!

Further details of changes are available in the change log available at: https://lucene.apache.org/core/9_3_0/changes/Changes.html.

Please report any feedback to the mailing lists (http://lucene.apache.org/core/discussion.html)

Note: The Apache Software Foundation now uses a content distribution network (CDN) for distributing releases.