Struct EstimationLog 

pub struct EstimationLog { /* private fields */ }

Collects estimate vs actual cardinality data for query plan analysis.

After executing a query, call record() for each operator with its estimated and actual cardinalities. Then use should_replan() to decide whether the plan should be re-optimized.

Implementations

impl EstimationLog

pub fn new(replan_threshold: f64) -> Self

Creates a new estimation log with the given re-planning threshold.

pub fn record( &mut self, operator: impl Into<String>, estimated: f64, actual: f64, )

Records an estimate-vs-actual observation.

pub fn entries(&self) -> &[EstimationEntry]

Returns all recorded entries.

pub fn should_replan(&self) -> bool

Returns whether any operator’s estimation error exceeds the threshold, indicating the plan should be re-optimized.

pub fn max_error_ratio(&self) -> f64

Returns the maximum error ratio across all entries.

pub fn clear(&mut self)

Clears all entries.

Trait Implementations

impl Clone for EstimationLog

fn clone(&self) -> EstimationLog

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EstimationLog

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

Formats the value using the given formatter.

impl Default for EstimationLog

fn default() -> EstimationLog

Returns the “default value” for a type.