Why don't any of the major RDBMS systems like MySQL, SQL Server, Oracle, etc. have good full text indexing support? I realize that most databases support full text indexes to some degree, but that they are usually slower, and with a smaller feature set.  It seems that every time you want a really good full text index, you have to go outside the database and use something like Lucene/Solr or Sphinx. Why isn't the technology in these full text search engines completely integrated into the database engine? There's lot of problems with keeping the data in another system such as Lucence, including keeping the data up to date, and the inability to join the results with other tables. Is there a specific technological reason why these two technologies can't be integrated? 
Why don't databases have good full text indexes
database;product features