Struct ExprStatisticsGraph

pub struct ExprStatisticsGraph { /* private fields */ }

This object implements a directed acyclic expression graph (DAEG) that is used to compute statistics/distributions for expressions hierarchically.

Implementations

impl ExprStatisticsGraph

pub fn try_new(expr: Arc<dyn PhysicalExpr>, schema: &Schema) -> Result<Self>

pub fn assign_statistics(&mut self, assignments: &[(usize, Distribution)])

This function assigns given distributions to expressions in the DAEG. The argument assignments associates indices of sought expressions with their corresponding new distributions.

pub fn evaluate_statistics(&mut self) -> Result<&Distribution>

Computes statistics/distributions for an expression via a bottom-up traversal.

pub fn propagate_statistics( &mut self, given_stats: Distribution, ) -> Result<PropagationResult>

Runs a propagation mechanism in a top-down manner to update statistics of leaf nodes.

Trait Implementations

impl Clone for ExprStatisticsGraph

fn clone(&self) -> ExprStatisticsGraph

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ExprStatisticsGraph

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

Formats the value using the given formatter.