In general, the subject matter described in this specification can be embodied in methods, systems, and program products for selecting a server from a plurality of servers to process a query. A query is converted into a query number. A hashing operation is performed on a combination of the query number and a second number that is associated with a present time interval. The hashing operation generates a hash value associated with the query and the present time interval. A length of the present time interval is increased as a quantity of servers in a plurality of servers increases. A server in the plurality of servers is selected to process the query, based on the hash value. The query is sent to the selected server.