According to one embodiment, a system may include a number of computing nodes configured to implement a number of index data structures each configured to map ones of a plurality of input values to one or more corresponding data items. Each of the index data structures may include a respective plurality of index nodes arranged hierarchically and each having an associated tag value, where each of the data items corresponds to a respective one of the index nodes, and where for a given one of the data items having a given corresponding index node, each tag value associated with each ancestor of the given corresponding index node is a prefix of a corresponding input value mapping to the given data item.