Struct CardinalityCheckpoint 

pub struct CardinalityCheckpoint {
    pub operator_id: String,
    pub estimated: f64,
    pub actual: u64,
    pub recorded: bool,
}

A checkpoint for tracking cardinality at a specific point in the plan.

Fields

operator_id: String

Unique identifier for this checkpoint (typically operator name/id).

estimated: f64

Estimated cardinality from the optimizer.

actual: u64

Actual row count observed during execution.

recorded: bool

Whether this checkpoint has been recorded.

Implementations

impl CardinalityCheckpoint

pub fn new(operator_id: &str, estimated: f64) -> Self

Creates a new checkpoint with an estimate.

pub fn record(&mut self, actual: u64)

Records the actual cardinality.

pub fn deviation_ratio(&self) -> f64

Returns the deviation ratio (actual / estimated).

A ratio > 1.0 means we underestimated, < 1.0 means overestimated. Returns 1.0 if estimate is 0 to avoid division by zero.

pub fn absolute_deviation(&self) -> f64

Returns the absolute deviation (|actual - estimated|).

pub fn is_significant_deviation(&self, threshold: f64) -> bool

Checks if this checkpoint shows significant deviation.

Trait Implementations

impl Clone for CardinalityCheckpoint

fn clone(&self) -> CardinalityCheckpoint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CardinalityCheckpoint

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

Formats the value using the given formatter.