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Lucene and Solr 4.8

· Big Data Zone

Today Apache Lucene and Solr PMC announced another version of Apache Lucene library and Apache Solr search server numbered 4.8. This is a next release continuing the 4th version of both Apache Lucene and Apache Solr. This is also the first version of Lucene that requires JDK 7.

Here are some of the changes that were made comparing to the 4.7.2:


  • First version of Lucene requiring JDK 1.7
  • New index format stores checksums for each file and can check them during merges
  • HunspellStemFilter uses 10 to 100x less memory and can open OpenOffice dictionaries without errors
  • Rescorer API was added to allow recalculating score for documents using more complicated functions
  • NativeFSLockFactory bug was fixed that allowed multiple IndexWriter instances obtain a lock
  • Multiple bug fixes and improvements since Lucene 4.7.2


  • Expand component was introduced – it allows to expand collapsing and block-join relationships
  • Added ADDREPLICA command to CollectionsAPI to allow easy replica creation
  • Complex phrase queries were added to Solr
  • <fields> and <types> tags in schema.xml are not mandatory anymore
  • REST API was added for synonyms and stopwords
  • Optimizations and bugfixes from Lucene 4.8

Full changes list for Lucene can be found at http://wiki.apache.org/lucene-java/ReleaseNote48. Full list of changes in Solr 4.8 can be found at: http://wiki.apache.org/solr/ReleaseNote48.

Apache Lucene 4.8 library can be downloaded from the following address: http://www.apache.org/dyn/closer.cgi/lucene/java/. Apache Solr 4.8 can be downloaded at the following URL address: http://www.apache.org/dyn/closer.cgi/lucene/solr/. Please remember that the mirrors are just starting to update so not all of them will contain the 4.8 version of Lucene and Solr.



Published at DZone with permission of Rafał Kuć , DZone MVB .

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