ThispaperintroducestheGeneralizedSearchTree(GiST),anindexstructuresupportinganextensiblesetofqueriesanddatatypes.TheGiSTallowsnewdatatypestobeindexedinamannersupportingqueriesnaturaltothetypes;thisisincontrasttopreviousworkontreeextensibilitywhichonlysupportedthetraditionalsetof