SOLR

:full_text_search
• Not relying on SQL statements
• Searching using multiple words in any order
• Stemming considerations (derived words)
• Results weighting
• Grouping (faceting)

:options
• MySQL queries (‘like ?’, “%#{text}%”)
• Ferret
• Sphinx / UltraSphinx
• Xapian (new)
• SOLR

acts_as_solr
• Based on the Lucene indexing and
searching engine, a free/open source libray
that was originally created in Java.
• http://en.wikipedia.org/wiki/Lucene
• Plugin, not a gem (yet)
• http://github.com/railsfreaks/acts_as_solr/
tree/master