_mobdb_span_joinsel _mobdb_span_sel calc_length_hist_frac get_len_position length_hist_bsearch span_bound_bsearch span_bound_distance span_const_to_span Span_joinsel span_joinsel span_joinsel_contained span_joinsel_contains span_joinsel_default span_joinsel_hist span_joinsel_hist1 span_joinsel_overlaps span_joinsel_scalar span_position Span_sel span_sel span_sel_contained span_sel_contains span_sel_default span_sel_hist span_sel_hist1 span_sel_overlaps span_sel_scalar time_oper_sel value_oper_sel

span_sel_overlaps() static double span_sel_overlaps ( const SpanBound *  const_lower, const SpanBound *  const_upper, const SpanBound *  hist_lower, const SpanBound *  hist_upper, int  nhist  ) static Calculate selectivity of "var && const" operator, i.e., estimate the fraction of spans that overlap the constant lower and upper bounds. This uses the histograms of span lower and upper bounds. Note that A && B <=> NOT (A <<# B OR A #>> B). Since A <<# B and A #>> B are mutually exclusive events we can sum their probabilities to find probability of (A <<# B OR A #>> B). "(span/spanset) @> timestamptz" is equivalent to "span && [elem,elem]". The caller already constructed the singular span from the element constant, so just treat it the same as &&.