datafusion_expr::interval_arithmetic

Function cardinality_ratio

Source 
pub fn cardinality_ratio(
    initial_interval: &Interval,
    final_interval: &Interval,
) -> f64
Expand description

This function computes the selectivity of an operation by computing the cardinality ratio of the given input/output intervals. If this can not be calculated for some reason, it returns 1.0 meaning fully selective (no filtering).