Struct KeyHeatStats 

pub struct KeyHeatStats {
    pub col_idx: usize,
    pub heat: f64,
    pub skew_factor: f64,
}

Per-key heat/skew statistics for one relation column.

The value is a compact summary of key-frequency imbalance. A value near zero is cold/unskewed; larger values indicate pivot-heavy keys that should be demoted by a skew-aware WCOJ planner.

Fields

col_idx: usize

Column index within the relation.

heat: f64

Heat value for the heavy-key tail.

skew_factor: f64

Multiplicative skew factor for the heaviest observed keys.

Implementations

impl KeyHeatStats

pub fn new(col_idx: usize, heat: f64, skew_factor: f64) -> Self

Creates key-heat statistics for a column.

Trait Implementations

impl Clone for KeyHeatStats

fn clone(&self) -> KeyHeatStats

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for KeyHeatStats

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.