Struct CostModel 

pub struct CostModel {
    pub graph_stats: Option<GraphStats>,
    pub column_stats: BTreeMap<String, ColumnStats>,
    pub physical_cost: CostEstimator,
}

Algebraic operator-tree cost model. Produces a unitless cost for each OperatorTree node so the query optimiser’s reorder_intersect pass can pick the lowest estimated join order.

Fields

graph_stats: Option<GraphStats>

column_stats: BTreeMap<String, ColumnStats>

physical_cost: CostEstimator

Implementations

impl CostModel

pub fn new() -> Self

pub fn with_graph_stats(self, stats: GraphStats) -> Self

pub fn with_column_stats(self, stats: BTreeMap<String, ColumnStats>) -> Self

pub fn with_cost_estimator(self, estimator: CostEstimator) -> Self

pub fn estimate(&self, op: &OperatorTree, stats: &IndexStats) -> f64

Estimate the cost of a subplan against stats.

Trait Implementations

impl Clone for CostModel

fn clone(&self) -> CostModel

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CostModel

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

Formats the value using the given formatter.

impl Default for CostModel

fn default() -> CostModel

Returns the “default value” for a type.