A system and method, including determining, by a processor, distinction bit positions for index keys of a database index; determining, by the processor, concatenation of the bits of the index keys; and generating a record of the concatenation. Other systems and methods include collecting, by a processor, index keys of a database index in parallel, wherein data pages of a target table are evenly distributed to a plurality of processor cores; scanning, by each of the cores the data pages to extract compressed keys and corresponding record identifiers; sorting, by a plurality of the processor cores, pairs of the compressed key and corresponding record identifier in accordance with a parallel sorting algorithm; generating an index tree in a bottom-up fashion; and storing a record of the generated index tree.