Struct ColumnStats 

pub struct ColumnStats {
    pub distinct_count: u64,
    pub null_count: u64,
    pub min_value: Option<f64>,
    pub max_value: Option<f64>,
    pub histogram: Option<EquiDepthHistogram>,
}

Statistics for a column.

Fields

distinct_count: u64

Number of distinct values.

null_count: u64

Number of null values.

min_value: Option<f64>

Minimum value (if orderable).

max_value: Option<f64>

Maximum value (if orderable).

histogram: Option<EquiDepthHistogram>

Equi-depth histogram for accurate selectivity estimation.

Implementations

impl ColumnStats

pub fn new(distinct_count: u64) -> Self

Creates new column statistics.

pub fn with_nulls(self, null_count: u64) -> Self

Sets the null count.

pub fn with_range(self, min: f64, max: f64) -> Self

Sets the min/max range.

pub fn with_histogram(self, histogram: EquiDepthHistogram) -> Self

Sets the equi-depth histogram for this column.

pub fn from_values(values: Vec<f64>, num_buckets: usize) -> Self

Builds column statistics with histogram from raw values.

This is a convenience method that computes all statistics from the data.

Arguments

• values - The column values (will be sorted internally)
• num_buckets - Number of histogram buckets to create

Trait Implementations

impl Clone for ColumnStats

fn clone(&self) -> ColumnStats

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ColumnStats

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

Formats the value using the given formatter.