MongoDB and Whoosh. Do I need both?

I am working on the project that uses MongoDB and Whoosh. I wonder if the Whoosh is necessary 开发者_C百科if I can use MongoDB search. I am sure Whoosh was setup in the system for good, but I am not sure I understand right its purpose. Please give me some idea about what it gives that MongoDB alone doesn't.

MongoDB search requires you to add keywords that you can later search on, so it's not really full text search (as Whoosh is). Whoosh can also do stemming (not available out of the box with MongoDB) and flexible scoring of results (including user-defined scoring).

Whoosh is a fast full-text searching and indexing library. MongoDB does not support full-text search, nor would it be as fast. Whoosh also has a great API and a lot of other features too. It should compliment MongoDB nicely.