12. The computer system of claim 11 , wherein the parent iterator is for: receiving, utilizing the parent iterator, first document information from the child iterator, the first document information being extracted from the postings list, receiving further document information from the further child iterator, the further document information being extracted from the further postings list, and performing at least one combinatorial operation on the first document information and the further document information to provide results responsive to the search request.
11. The computer system of claim 10 , wherein the computer-readable storage medium has further computer-executable instructions stored thereon which, when executed by the processor, cause the processor to perform the method further comprising: traversing at least the further child iterator through at least a portion of at least a further postings list in response to the search request; updating at least one instance of the third dynamic state information in response to traversing the further child iterator through at least a portion of the further postings list; storing the third checkpoint in the third stack structure, the third checkpoint comprising the third dynamic state information; and restoring at least the further child iterator to the previous state by copying the third dynamic state information from the third checkpoint.