Six weeks after entering alpha, version 4.0 of Apache's Lucene search engine and Solr, the search platform built on top of Lucene, have now been released as beta software. The 4.0 release is most notable for bringing easy scaling to Solr installations through SolrCloud. There are also more NoSQL features being added to Solr to allow it to work better as a primary data store. Lucene itself is receiving many other under-the-hood improvements including better indexing, faster fuzzy queries and more efficient in-memory storage.

The beta version of Lucene sees new functions for document deletion, experimental posting formats, improvements to CJK analysis, improved Scorer API and various other API changes. A collection management API and delete-by-query support for Solr Cloud, clearer display of failures in the Solr Admin UI, document updates that create documents if one doesn't exist, and improved Solrj client performance are among the Solr enhancements in the beta.

Lucene 4.0 beta is available to download from project mirrors, as is beta 4.0 for Solr. There is no release date for the final versions of Lucene and Solr 4.0, but they will be in beta for at least a month. As usual, development versions are only recommended for testing; for production use, the current stable versions of Lucene/Solr – 3.6.1 – are preferred.

(djwm)