Thanks a lot. That's very helpful. I think you get exactly what I mean about the LUCENE-4396. By grouping up the MUST clauses, the conjunctive query can be done specifiedly with easy way. Then, the original query would have no more than 1 MUST clause. I think in this situation, it's much more easier to judge whether to use BooleanScorer or BooleanScorer2. :)
Thanks, Da Huang -- 黄达（Da Huang） Team of Search Engine & Web Mining School of Electronic Engineering & Computer Science Peking University, Beijing, 100871, P.R.China
