Struct ExprStatisticsGraphNode 

pub struct ExprStatisticsGraphNode {
    expr: Arc<dyn PhysicalExpr>,
    dist: Distribution,
}

This is a node in the DAEG; it encapsulates a reference to the actual PhysicalExpr as well as its statistics/distribution.

Fields

expr: Arc<dyn PhysicalExpr>

dist: Distribution

Implementations

impl ExprStatisticsGraphNode

fn new_uniform(expr: Arc<dyn PhysicalExpr>, interval: Interval) -> Result<Self>

Constructs a new DAEG node based on the given interval with a Uniform distribution.

fn new_bernoulli(expr: Arc<dyn PhysicalExpr>) -> Result<Self>

Constructs a new DAEG node with a Bernoulli distribution having an unknown success probability.

fn new_generic(expr: Arc<dyn PhysicalExpr>, dt: &DataType) -> Result<Self>

Constructs a new DAEG node with a Generic distribution having no definite summary statistics.

pub fn distribution(&self) -> &Distribution

Get the [Distribution] object representing the statistics of the expression.

pub fn make_node( node: &ExprTreeNode<NodeIndex>, schema: &Schema, ) -> Result<Self>

This function creates a DAEG node from DataFusion’s ExprTreeNode object. Literals are created with Uniform distributions with a definite, singleton interval. Expressions with a Boolean data type result in aBernoulli distribution with an unknown success probability. Any other expression starts with an Unknown distribution with an indefinite range (i.e. [-∞, ∞]).

Trait Implementations

impl Clone for ExprStatisticsGraphNode

fn clone(&self) -> ExprStatisticsGraphNode

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ExprStatisticsGraphNode

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

Formats the value using the given formatter.