Method merge

nodedb-array/src/query/aggregate.rs:62–112

Merge two partials of the same reducer kind. Mismatched reducers produce a left-biased result (the executor only ever merges same-kind partials, so this is a programming-error path).

(self, other: AggregateResult)

    /// reducers produce a left-biased result (the executor only ever
    /// merges same-kind partials, so this is a programming-error path).
    pub fn merge(self, other: AggregateResult) -> AggregateResult {
        use AggregateResult::*;
        match (self, other) {
            (Empty(_), x) | (x, Empty(_)) => x,
            (
                Sum {
                    value: a,
                    count: ca,
                },
                Sum {
                    value: b,
                    count: cb,
                },
            ) => Sum {
                value: a + b,
                count: ca + cb,
            },
            (Count { count: a }, Count { count: b }) => Count { count: a + b },
            (
                Min {
                    value: a,
                    count: ca,
                },
                Min {
                    value: b,
                    count: cb,
                },
            ) => Min {
                value: if a <= b { a } else { b },
                count: ca + cb,
            },
            (
                Max {
                    value: a,
                    count: ca,
                },
                Max {
                    value: b,
                    count: cb,
                },
            ) => Max {
                value: if a >= b { a } else { b },
                count: ca + cb,
            },
            (Mean { sum: a, count: ca }, Mean { sum: b, count: cb }) => Mean {
                sum: a + b,
                count: ca + cb,
            },
            (lhs, _) => lhs,
        }
    }

    /// Final scalar — useful for tests and the planner's last fold.
    pub fn finalize(self) -> Option<f64> {