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ColumnStats

uqa_planner::cardinality

Struct ColumnStats 

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pub struct ColumnStats {
    pub distinct_count: u64,
    pub null_count: u64,
    pub min_value: Option<Value>,
    pub max_value: Option<Value>,
    pub row_count: u64,
    pub histogram: Vec<Value>,
    pub mcv_values: Vec<Value>,
    pub mcv_frequencies: Vec<f64>,
}

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§distinct_count: u64§null_count: u64§min_value: Option<Value>§max_value: Option<Value>§row_count: u64§histogram: Vec<Value>

Equi-depth histogram bucket boundaries, sorted ascending. b+1 boundaries describe b buckets.

§mcv_values: Vec<Value>

Most-common values, descending by frequency.

§mcv_frequencies: Vec<f64>

Implementations§

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impl ColumnStats

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pub fn equality_selectivity(&self) -> f64

Default selectivity of an equality predicate over this column.

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pub fn non_null_fraction(&self) -> f64

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pub fn equality_selectivity_for(&self, value: &Value) -> f64

An equality constant outside the MCV list shares only its remaining probability mass.

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pub fn matches_mcv(&self, value: &Value) -> Option<f64>

Trait Implementations§

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impl Clone for ColumnStats

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fn clone(&self) -> ColumnStats

Returns a duplicate of the value. Read more
1.0.0 (const: unstable) · Source§

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

Performs copy-assignment from source. Read more
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impl Debug for ColumnStats

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

Formats the value using the given formatter. Read more
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impl Default for ColumnStats

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fn default() -> ColumnStats

Returns the “default value” for a type. Read more

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fn borrow_mut(&mut self) -> &mut T

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
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