18. The system of claim 11 , the instructions further comprising instructions to perform at least one of: determine that the query template is a candidate for precomputing; and precompute an answer to the query in an online fashion.
18. The system of claim 11 , the instructions further comprising instructions to perform at least one of: determine that the query template is a candidate for precomputing; and precompute an answer to the query in an online fashion. 19. The system of claim 18 , wherein the query is a dense query, and wherein the precomputing occurs in a background in an interruptible process that terminates soon after a new query is received.