1. One or more computer-storage memory storing computer-useable instructions that, when used by a computing device, cause the computing device to perform a method for assigning a segment root, the method comprising: receiving a search query; identifying a set of nodes in a segment that will be used to resolve the search query, the segment is assigned a group of documents indexed by atom in a reverse index and indexed by document in a forward index, wherein corresponding portions of the reverse index and forward index are apportioned to each node in the set of nodes, and wherein the reverse index is used for a preliminary ranking process and the forward index is used for a final ranking process; selecting a preliminary segment root from the set of nodes; receiving, at the preliminary segment root, statistical data from each node in the identified set of nodes, the statistical data indicating each node's capability to act as a final segment root that is responsible for assembling query-execution results from the set of nodes based on the search query, wherein the statistical data is generated based on, at least in part, the preliminary ranking process and the final ranking process; algorithmically selecting the final segment root from the set of nodes based on the statistical data; and notifying the set of nodes about the final segment root so that the nodes know where to send their respective query-execution results.