1. In a computerized search system in which queries are submitted by users who receive, in response, a list of documents selected from a corpus of documents wherein the list comprises documents deemed responsive to a user's query, a method of processing the query comprising: obtaining a query from a user; distributing the query to a number of independent computational nodes, each computational node configured to search a corresponding segment of an index of the corpus of documents, the number of computational nodes being greater than one; running the query in each of the computational nodes against the corresponding segment of the index of the corpus of documents to obtain from each of the computational nodes an intermediate results list of zero or more documents in the document corpus deemed responsive to the query; identifying a desired probability of not retrieving one most responsive result in an aggregated number of results in an aggregated list of results; determining a number of results to retrieve from each of the intermediate results lists obtained from the computational nodes, the number of results being determined to provide a determinable probability of not retrieving one most responsive result in the aggregated number of results in the aggregated list of results, the determinable probability being less than or equal to the desired probability of not retrieving one most responsive result in the aggregated list of results, where the determined number of results is less than the aggregated number of results, the determinable probability being determined based on an estimated distribution of documents among the computational nodes and further based on the number of computational nodes; and aggregating the determined number of results from each of the intermediate results lists containing the determined number of results or more into the aggregated list of results, otherwise aggregating all results from each of the intermediate results lists containing fewer than the determined number of results into the aggregated list of results.