De Apache Software Foundation heeft een nieuwe versie van Lucene uitgebracht met 9.2.0 als versienummer. Lucene kan worden ingezet als onderdeel van een zoekmachine. Het kan namelijk volledige tekstindexering uitvoeren. Solr kan vervolgens worden ingezet als een zoekmachine waarbij het op de achtergrond gebruikmaakt van Lucene en draait als een Java Servlet binnen bijvoorbeeld Tomcat. Voorheen werd met een nieuwe versie van Lucene ook een nieuwe versie van Solr uitgebracht. Solr is echter begin 2021 afgesplitst als subproject van Lucene en is sindsdien een Apache TLP. De aankondiging van deze uitgave ziet er als volgt uit:
Apache Lucene 9.2.0 available
The Lucene PMC is pleased to announce the release of Apache Lucene 9.2.0.
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 across high-dimensionality vectors, spell correction or query suggestions.
This release contains numerous bug fixes, 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 9.2.0 Release Highlights:Please read CHANGES.txt for a full list of new features and changes: https://lucene.apache.org/core/9_2_0/changes/Changes.html
- Numerous improvements to indexing and query performance for KNN vectors
- More efficient implementations for count operations on range queries
- A new FieldExistsQuery that chooses the best index structures to run over for you
- A new Persian stemmer
Lucene 9.1.0 Release Highlights:Lucene 9.0.0 Release Highlights:
- New features
- Lucene JARs are now proper Java modules, with module descriptors and dependency information
- Support for filtering in nearest-neighbor vector search
- Support for intervals queries in the standard query syntax
- A new token filter SpanishPluralStemFilter for precise stemming of Spanish plurals
- Optimizations
- Up to 30% improvement in index throughput for high-dimensional vectors
- Up to 10% faster nearest neighbor searches on high-dimensional vectors
- Faster execution of "count" searches across different query types
- Faster counting for taxonomy facets
- Several other search speed-ups, including improvements to PointRangeQuery, MultiRangeQuery, and CoveringRangeQuery
- Other
- The test framework is now a module, so all classes have been moved from to org.apache.lucene.tests.* to avoid package name conflicts
- Lucene now faithfully implements the HNSW algorithm for nearest neighbor search by supporting multiple graph layers
- … plus a number of helpful bug fixes!
- System requirements
- Lucene 9.0 requires JDK 11 or newer
- New features
- Support for indexing high-dimensionality numeric vectors to perform nearest-neighbor search, using the Hierarchical Navigable Small World graph algorithm
- New Analyzers for Serbian, Nepali, and Tamil languages
- IME-friendly autosuggest for Japanese
- Snowball 2, adding Hindi, Indonesian, Nepali, Serbian, Tamil, and Yiddish stemmers
- New normalization/stemming for Swedish and Norwegian
- Optimizations
- Up to 400% faster taxonomy faceting
- 10-15% faster indexing of multi-dimensional points
- Several times faster sorting on fields that are indexed with points. This optimization used to be an opt-in in late 8.x releases and is now opt-out as of 9.0.
- ConcurrentMergeScheduler now assumes fast I/O, likely improving indexing speed in case where heuristics would incorrectly detect whether the system had modern I/O or not
- Encoding of postings lists changed from FOR-delta to PFOR-delta to save further disk space
- Other
- File formats have all been changed from big-endian order to little endian order
- Lucene 9 no longer has split packages. This required renaming some packages outside of the lucene-core JAR, so you will need to adjust some imports accordingly.
- Using Lucene 9 with the module system should be considered experimental. We expect to make progress on this in future 9.x releases.
