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June 24, 2015
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Announcing Apache Solr 5.2 Release

The Apache Lucene/Solr community is continuing its rapid release cycles to meet community and customer requirements. In this guest blog, we have invited Sarath Jarugula from Lucidworks to share with us the many improvements in the Apache Solr 5.2 release.

The Apache Solr community has announced its Solr 5.2 release. Solr 5.2 is a follow-up release to Solr 5.0, a significant major release in February 2015. The community has delivered 25 new features, 5 optimizations, and 38 bug fixes in this release.

Solr is now an integral part of the Apache Hadoop ecosystem, and has become a key component of the Hortonworks Data Platform (HDP). Using Apache Solr and the Hortonworks Data Platform, enterprises are able to realize use cases supporting both batch and real-time processing needs.

Notable Changes


For the first time, Solr offers a security framework to support authentication and authorization. You can read detail description of Solr’s security features here.


Authentication plugins help in securing the endpoints of Solr by authenticating incoming requests. Solr’s AuthenticationPlugin class can now be extended to implement a custom security plugin. Solr 5.2 also includes Kerberos authentication plugin out-of-the-box, allowing customers to run Kerberos-enabled Hadoop and Solr together.


To authorize end-user access to your Solr collections, you can extend the AuthorizationPlugin interface to implement your authorization policies. Apache Ranger will utilize this to implement a central mechanism to define and enforce authorization for Solr collections.

Replication Enhancements

For reliable replication, administrators can now configure two enhancements:

  • HDFS transaction log replication factor; and
  • Rule-based replica assignment during collection, shard, and replica creation

Performance Improvements

Also, with this release comes a substantial indexing performance improvement. Compared to Solr 4.x., performance is improved by almost 100%.

Facet Enhancements

A number of facet improvements cater to faceted queries. For example, additional fields and display range allow for controlled queries; others improvements include:

  • JSON Facet API now supports numeric, date facets, and use type parameters for a flatter request.
  • Exclude displaying range facet if the facet count doesn’t meet minimum criteria.
  • Solr stats component now has support for HyperLogLog based cardinality estimation. Use this stats component to trade off accuracy for the amount of RAM used at query time, with relatively minor impacts on response time performance.

Learn More about Solr 5.2



Hari Sekhon says:

Glad to see Solr finally getting open source authentication and authorization – hopefully Elasticsearch will follow suit and I won’t have to keep building authenticated proxies…

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