bbox_gist_consider_split bbox_gist_fallback_split bbox_gist_picksplit interval_cmp_lower interval_cmp_upper non_negative PLACE_LEFT PLACE_RIGHT tbox_adjust Tbox_gist_distance Tbox_gist_penalty Tbox_gist_picksplit Tbox_gist_same Tbox_gist_union tbox_penalty tbox_size tbox_union_rt Tnumber_gist_compress Tnumber_gist_consistent tnumber_gist_get_tbox

Tbox_gist_distance() Datum Tbox_gist_distance ( PG_FUNCTION_ARGS  ) GiST support distance function that takes in a query and an entry and returns the "distance" between them.