If you're seeing a lot of email traffic, you need to move the indexing to an actual external search engine and write your own 'search' plugin; both Lucene and S

If you're seeing a lot of email traffic, you need to move the indexing to an actual external search engine and write your own 'search' plugin; both Lucene and Sphinx would rape native TB search in performance. And the index can be shared across a team as well, say, in a sales force.