Solr is the Lucene search server; it that transforms Lucene into an enterprise search platform. Like Lucene, which it contains, Solr is free open source available under the liberal Apache Software License. Solr provides the following capabilities:

• Web service: Solr places Lucene over HTTP, allowing programs written in any language to invoke Lucene.
• XML based schema for managing indexed fields and their characteristics.
• Admin tools for configuration, data loading, index replication, statistics, logging and cache management
• Large scale distributed search
• Fixed/paid result list placement
• Faceting — the dynamic clustering of items or search results into categories that let users drill into search results (or even skip searching entirely) by any value in any field, as seen in popular e-commerce sites such as Amazon or Zappos.

Most users building Lucene-based search applications will find they can do so more quickly if they start with Solr, as it contains many of the capabilities needed to turn a core search function into a full-fledged search application.

Download the Certified Distribution of Solr