async fn count_pair(
api: &Api,
r: &Rule,
now: i64,
) -> Result<(f64, usize, Option<usize>, Option<String>), String>Expand description
Run a rule’s queries and reduce them to one number.
Two scans for a ratio, not one over a superset filtered twice: the terms are AND-ed and the denominator is a different conjunction, so there is no single scan that answers both, and two exact counts beat one estimate.