The Lucene PMC is pleased to announce the release of Apache Lucene 9.11.0. 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 9.11.0 Release Highlights: New features: * Add support for posix_madvise to MMapDirectory: If running on Linux/macOS and Java 21 or later, MMapDirectory uses IOContext to pass suitable MADV flags to the kernel of the operating system. This may improve paging logic especially when working with large indexes under memory pressure. * Expand support for new scalar bit levels for HNSW vectors. This includes 4-bit vectors and an option to compress them to gain a 50% reduction in memory usage. * Recursive graph bisection is now supported on indexes that have blocks Improvements: * MergeScheduler can now provide an executor for intra-merge parallelism. The first implementation is the ConcurrentMergeScheduler. * Upgrade icu4j to version 74.2. Optimizations: * Use RWLock to access LRUQueryCache to reduce contention. * Speedup multi-segment HNSW graph search for diversifying child kNN queries. * Add a MemorySegment Vector scorer - for scoring without copying on-heap. This can improve search latency by almost 2x for byte vectors. * Switch to using optimized, primitive collections where possible to improve performance and heap utilization. ...And many more optimizations and bugfixes. Please read CHANGES.txt for a full list of new features and changes: https://lucene.apache.org/core/9_11_0/changes/Changes.html Please report any feedback to the mailing lists ( http://lucene.apache.org/core/discussion.html) Note: The Apache Software Foundation uses an extensive mirroring network for distributing releases. It is possible that the mirror you are using may not have replicated the release yet. If that is the case, please try another mirror. This also applies to Maven access.
