Apache Solr 6.0.0 发布了，一些提升：
  * The deprecated <nrtMode> configuration in solrconfig.xml has been
removed. Users must remove it from solrconfig.xml.

  * SolrClient.shutdown() has been removed, use SolrClient.close() instead.

  * The deprecated zkCredientialsProvider element in solrcloud section of
solr.xml is now removed. Use the correct spelling (zkCredentialsProvider)
instead.

  * Added support for executing Parallel SQL queries across SolrCloud
collections. Includes StreamExpression support and a new JDBC Driver for
the SQL Interface.

  * New features and capabilities added to the streaming API.

  * Added support for SELECT DISTINCT queries to the SQL interface.

  * New GraphQuery to enable graph traversal as a query operator.

  * New support for Cross Data Center Replication consisting of

下载地址：http://lucene.apache.org/solr/mirrors-solr-latest-redir.html

Solr是一个高性能，采用Java开发，基于Lucene的全文搜索服务器。文档通过Http利用XML加到一个搜索集合中。查询该集合也是通过 http收到一个XML/JSON响应来实现。它的主要特性包括：高效、灵活的缓存功能，垂直搜索功能，高亮显示搜索结果，通过索引复制来提高可用性，提 供一套强大Data Schema来定义字段，类型和设置文本分析，提供基于Web的管理界面等。