I don't think that's true. From what I perused of the driver implementations, I think that as calls are made, the driver basically builds an AST up, and then when you call run() it compacts it and sends it over to the DB. ie, when you call filter() you aren't actually filtering, you're adding a filter operation to the AST.
I would think that would allow Rethink to analyze the structure of the query and perform appropriate optimizations.
I would think that would allow Rethink to analyze the structure of the query and perform appropriate optimizations.