Search Engine Information / MediaWiki Search Extension

Platform: Unix, Linux , Windows, MacOS X (written in C++)
Price: free open source under GPL.

Features

• Indexes via SphinxSE direct connection to MySQL or PostgreSQL
• Accepts data in XML format from using the Sphinx API
• Note that this package does not include a robot spider for traversing web sites.
• High-speed indexing, up to 10 MB/sec on fast CPU
• Can store up to 100 GB text / 100 million documents on a single CPU
• Indexes any number of fields and metadata tags, can be changed on the fly
• Stemming for English and Russian words
• Simple search modes, "match all", "match any", "match phrase"
  
• Also supports Boolean expressions (using &, |, -, and parentheses)
• Field searching, wildcarding, and proximity operators
• Fast searching (under 0.1 second on 2-4 GB index)
• Stemming query processing English and Russian natively, and with libstemmer for French, Spanish, Portuguese, Italian, German, Dutch, Swedish, Norwegian, Danish, Finnish, Hungarian
• Relevance based on BM25, (a flavor of TF:IDF) and phrase-based ranking.
• Sort by relevance, metadata in ascending or descending order, time range, or a SQL-like expression
• Group results by day, week, month, year, or an attribute value, and show only the best match per group.
• Can adjust relevance according to fields (even at runtime)
• Options for faceted metadata display
• XML results interface for custom integration
• Can replace SQL WHERE, ORDER BY, and GROUP BY query elements
• APIs for PHP, Python, Java, Perl, and Ruby
• Can utilize many CPU cores
• Distributed search - multiple search engines can search segmented indexes on multiple machines.
• Scales to at least 1.2 billion records, 30 million searches per day on a 15-server installation
• Source code and binaries available
• Administration by config file

Articles & Reviews

• Installing Sphinx & Ultrasphinx on Windows Cordinc Blog: March 26, 2008 by Charles
  Notes about how to install Sphinx and make it work with Ruby on Rails.
  
• Searching database content with Sphinx Linux.com: August 24, 2007 by Frederico Kereki
  Nice overview and introduction to Sphinx.
  
• Build a custom search engine with PHP IBM developerworks: July 31, 2007 by Martin Streicher
  
  A hands-on how-to article using an example of auto-body parts, a complex MySQL table to store the data, and Sphinx
  to search, especially for "OR" searches and complex queries.
• Sphinx: Going Beyond full text search MySQL Performance Blog: July 23, 2007 by peter
  Describes using Sphinx to do hundreds of thousands of queries per day against a billion forum posts at boardreader.com
• PHP Search Engine Showdown ONLamp.com : April 03, 2007 , by Michael Douma
  
  First page has a nice overview of site search for database-backed sites, second page has quick reviews of iSearch (1 star), MnogoSearch (3 stars), PHPDig (2 stars), RiSearch (1 star), Sphider (3 stars), Sphinx( 3 stars). and TSEP
  (two stars).

Examples

• Apartment Therapy - interior and exterior design, social networking site
• eScience News - popular science news aggregator
• Helsingborgs Dagblad - a large newspaper in Sweden.
• Absorbent Printing - custom promotional and corporate gift printing
• New World Encyclopedia - an online encyclopedia