WOOHOO! On Fri, Oct 12, 2012 at 10:34 AM, Uwe Schindler <[email protected]> wrote: > Thanks Robert for doing the hard work of managing this release! > > I am happy that the release finally came out, after a long time of > development, code refactoring, and lots of non-finite beer-automatons! > > Uwe > ----- > Uwe Schindler > H.-H.-Meier-Allee 63, D-28213 Bremen > http://www.thetaphi.de > eMail: [email protected] > > >> -----Original Message----- >> From: Robert Muir [mailto:[email protected]] >> Sent: Friday, October 12, 2012 10:10 AM >> To: [email protected]; Lucene mailing list; java-user; announce >> Subject: [ANNOUNCE] Apache Lucene 4.0 released. >> >> October 12 2012, Apache Lucene‚ 4.0 available. >> The Lucene PMC is pleased to announce the release of Apache Lucene 4.0 >> >> 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://lucene.apache.org/core/mirrors-core-latest-redir.html >> >> See the CHANGES.txt file included with the release for a full list of >> details. >> >> Lucene 4.0 Release Highlights: >> >> * The index formats for terms, postings lists, stored fields, term vectors, >> etc >> are pluggable via the Codec api. You can select from the provided >> implementations or customize the index format with your own Codec to meet >> your needs. >> >> * Similarity has been decoupled from the vector space model (TF/IDF). >> Additional models such as BM25, Divergence from Randomness, Language >> Models, and Information-based models are provided (see >> http://www.lucidimagination.com/blog/2011/09/12/flexible-ranking-in-lucene- >> 4). >> >> * The new doc values feature stores typed values per-document. It can be >> used for custom scoring factors (accessible via Similarity), for pre-sorted >> Sort >> values, and more. >> >> * IndexWriter now flushes segments to disk concurrently, when the >> application >> uses multiple threads for indexing, resulting in substantial performance >> improvements (see http://blog.mikemccandless.com/2011/05/265-indexing- >> speedup-with-lucenes.html). >> >> * Per-document normalization factors ("norms") are no longer limited to a >> single byte. Similarity implementations can use any DocValues type to store >> norms. >> >> * New index statistics have been added, including the number of tokens for a >> term or field, number of postings for a field, and number of documents with a >> posting for a field. These support additional scoring models (see >> http://blog.mikemccandless.com/2012/03/new-index-statistics-in-lucene- >> 40.html). >> >> * A new default term dictionary/index (BlockTree) indexes shared prefixes >> instead of every n'th term. This is not only more time- and >> space- efficient, but can avoid going to disk at all for terms that do not >> exist in >> certain cases. Alternative term dictionary implementions are provided and >> pluggable via the Codec api. >> >> * Indexed terms are no longer limited to UTF-16 char sequences; they can now >> be any binary value encoded as byte arrays. By default, text terms are >> encoded >> as UTF-8 bytes. Sort order of terms is defined by their binary value, which >> is >> identical to UTF-8 (Unicode code point) sort order. >> >> * Substantially faster performance when using a Filter during searching. >> >> * File-system based directories can rate-limit the IO (MB/sec) of merge >> threads, to reduce IO contention between merging and searching threads. >> >> * A number of alternative Codecs and components have been added: >> "Appending" works with append-only filesystems (such as Hadoop DFS), >> "Memory" writes the entire terms+postings as an FST read into RAM (see >> http://blog.mikemccandless.com/2011/06/primary-key-lookups-are-28x-faster- >> with.html), >> "Pulsing" inlines the postings for low-frequency terms into the term >> dictionary >> (see http://blog.mikemccandless.com/2010/06/lucenes-pulsingcodec-on- >> primary-key.html), >> "SimpleText" writes all files in plain-text for easy debugging/transparency >> (see >> http://blog.mikemccandless.com/2010/10/lucenes-simpletext-codec.html), >> "Bloom" uses a bloom filter to sometimes avoid disk seeks when looking up >> terms, "Direct" holds all postings as simple byte[] and int[] for very fast >> performance at the cost of very high RAM consumption, "Block" use a new >> index layout and compression scheme for improved performance, among >> others. >> >> * Term offsets can be optionally encoded into the postings lists and >> retrieved >> per-position. >> >> * A new AutomatonQuery returns all documents containing any term matching >> a provided finite-state automaton (see >> http://www.slideshare.net/otisg/finite- >> state-queries-in-lucene). >> >> * FuzzyQuery is 100-200 times faster than in past releases (see >> http://blog.mikemccandless.com/2011/03/lucenes-fuzzyquery-is-100-times- >> faster.html). >> >> * A new spell checker, DirectSpellChecker, finds possible corrections >> directly >> against the main search index without requiring a separate index. >> >> * Various in-memory data structures such as the term dictionary and >> FieldCache are represented more efficiently with less object overhead (see >> http://blog.mikemccandless.com/2010/07/lucenes-ram-usage-for- >> searching.html). >> >> * All search logic is now required to work per segment, IndexReader was >> therefore refactored to differentiate between atomic and composite readers >> (see http://blog.thetaphi.de/2012/02/is-your-indexreader-atomic-major.html). >> >> * Lucene 4.0 provides a modular API, consolidating components such as >> Analyzers and Queries that were previously scattered across Lucene core, >> contrib, and Solr. These modules also include additional functionality such >> as >> UIMA analyzer integration and a completely reworked spatial search >> implementation. >> >> Noteworthy changes since 4.0-BETA: >> >> * A new "Block" PostingsFormat offering improved search performance and >> index compression. This will likely become the default format in a future >> release. (see http://blog.mikemccandless.com/2012/08/lucenes-new- >> blockpostingsformat-thanks.html). >> >> * All non-default codec implementations were moved to a separated codecs >> module. Just add lucene-codecs-4.0.0.jar to your classpath to test these out. >> >> * Payloads can be optionally stored on the term vectors. >> >> * Many bugfixes and optimizations. >> >> Please read CHANGES.txt and MIGRATE.txt for a full list of new features and >> notes on upgrading. Particularly, the new apis are not compatible with >> previous >> versions of Lucene, however, file format backwards compatibility is provided >> for indexes from the 3.0 series and the 4.0-alpha and -beta releases. >> >> 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 goes for Maven access. >> >> Happy searching, >> >> Apache Lucene/Solr Developers > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] >
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