* Sphinx search (free, open source): http://sphinxsearch.com http://sphinxsearch.com , http://en.wikipedia.org/wiki/Sphinx_(search_engine) http://en.wikipedia.o

* Sphinx search (free, open source): http://sphinxsearch.com http://sphinxsearch.com , http://en.wikipedia.org/wiki/Sphinx_(search_engine) http://en.wikipedia.org/wiki/Sphinx_(search_engine) It's the lightweight & fast alternative, similar to what Nginx is to Apache and IIS. * SQLite FTS 4 (free, open source): http://www.sqlite.org/fts3.html http://www.sqlite.org/fts3.html Lightweight & embedded solution (suitable for small to medium sized database and single process).