Struct ColumnStatistics 

pub struct ColumnStatistics {
    pub null_count: Precision<usize>,
    pub max_value: Precision<ScalarValue>,
    pub min_value: Precision<ScalarValue>,
    pub sum_value: Precision<ScalarValue>,
    pub distinct_count: Precision<usize>,
    pub byte_size: Precision<usize>,
}

Statistics for a column within a relation

Fields

null_count: Precision<usize>

Number of null values on column

max_value: Precision<ScalarValue>

Maximum value of column

min_value: Precision<ScalarValue>

Minimum value of column

sum_value: Precision<ScalarValue>

Sum value of a column

distinct_count: Precision<usize>

Number of distinct values

byte_size: Precision<usize>

Estimated size of this column’s data in bytes for the output.

Note that this is not the same as the total bytes that may be scanned, processed, etc.

E.g. we may read 1GB of data from a Parquet file but the Arrow data the node produces may be 2GB; it’s this 2GB that is tracked here.

Currently this is accurately calculated for primitive types only. For complex types (like Utf8, List, Struct, etc), this value may be absent or inexact (e.g. estimated from the size of the data in the source Parquet files).

This value is automatically scaled when operations like limits or filters reduce the number of rows (see Statistics::with_fetch).

Implementations

impl ColumnStatistics

pub fn is_singleton(&self) -> bool

Column contains a single non null value (e.g constant).

pub fn new_unknown() -> Self

Returns a ColumnStatistics instance having all Precision::Absent parameters.

pub fn with_null_count(self, null_count: Precision<usize>) -> Self

Set the null count

pub fn with_max_value(self, max_value: Precision<ScalarValue>) -> Self

Set the max value

pub fn with_min_value(self, min_value: Precision<ScalarValue>) -> Self

Set the min value

pub fn with_sum_value(self, sum_value: Precision<ScalarValue>) -> Self

Set the sum value

pub fn with_distinct_count(self, distinct_count: Precision<usize>) -> Self

Set the distinct count

pub fn with_byte_size(self, byte_size: Precision<usize>) -> Self

Set the scan byte size This should initially be set to the total size of the column.

pub fn to_inexact(self) -> Self

If the exactness of a ColumnStatistics instance is lost, this function relaxes the exactness of all information by converting them Precision::Inexact.

Trait Implementations

impl Clone for ColumnStatistics

fn clone(&self) -> ColumnStatistics

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ColumnStatistics

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

Formats the value using the given formatter.

impl Default for ColumnStatistics

fn default() -> ColumnStatistics

Returns the “default value” for a type.

impl PartialEq for ColumnStatistics

fn eq(&self, other: &ColumnStatistics) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for ColumnStatistics

impl StructuralPartialEq for ColumnStatistics