Lucene and Solr 3.4.0 Released

The Apache Lucene community has just released Lucene 3.4.0 and Solr 3.4.0.

You can read the official announcements here and here.

There are several juicy additions, but also a critical bug fix.  It is recommended that all 3.x-using applications upgrade to 3.4 as soon as possible.  Here’s the scoop on this fixed bug:

* Fixed a major bug (LUCENE-3418) whereby a Lucene index could
  easily become corrupted if the OS or computer crashed or lost
  power.

Lucene 3.4.0 includes:  a new faceting module (contrib/facet) for computing facet counts (both hierarchical and non-hierarchical) at search time (LUCENE-3079);  a new join module (contrib/join), enabling indexing and searching of nested (parent/child) documents using  (LUCENE-3171);  ability to now to index documents with term frequencies included but without positions (LUCENE-2048) – previously omitTermFreqAndPositions always omitted both; and a few other improvements.

Solr 3.4.0 includes: Lucene 3.4.0, which fixes the serious bug mentioned above; a new XsltUpdateRequestHandler allows posting XML that’s transformed by a provided XSLT into a valid Solr document (SOLR-2630); field grouping/collapsing: post-group faceting option (group.truncate) can now compute facet counts for only the highest ranking documents per-group (SOLR-2665); The query cache and filter cache can now be disabled per request (SOLR-2429); Improved memory usage, build time, and performance of SynonymFilterFactory (LUCENE-3233); various fixes for multi-threaded DataImportHandler; and a few other improvements.

Here are the links for more information and download access: Lucene 3.4.0 and Solr 3.4.0