Apparatus and method for highly efficient data queries. In accordance with various embodiments, a data structure is provided in a memory space with a first portion characterized as a virtual data space storing non-sequential entries and a second portion characterized as a first data array of sequential entries. At least a first sequential entry of the data array points to a skip list, at least a second sequential entry of the data array points to a second data array, and at least a third sequential entry points to a selected non-sequential entry in the first portion.