Struct QueryStats 

pub struct QueryStats {
    pub query_hash: u64,
    pub actual_rows: usize,
    pub estimated_rows: usize,
    pub execution_time_ms: u64,
    pub join_order: Vec<String>,
    pub selectivity_by_pattern: HashMap<String, f64>,
}

Statistics recorded for a single query execution.

Fields

query_hash: u64

Hash of the query string (see AdaptiveQueryOptimizer::hash_query).

actual_rows: usize

Number of rows actually produced.

estimated_rows: usize

Number of rows the optimizer estimated would be produced.

execution_time_ms: u64

Wall-clock time consumed by the execution, in milliseconds.

join_order: Vec<String>

The join order that was used, as a list of pattern descriptions.

selectivity_by_pattern: HashMap<String, f64>

Per-pattern selectivities observed during execution.

Implementations

impl QueryStats

pub fn new( query_hash: u64, actual_rows: usize, estimated_rows: usize, execution_time_ms: u64, join_order: Vec<String>, selectivity_by_pattern: HashMap<String, f64>, ) -> Self

Construct a new QueryStats value.

pub fn accuracy_ratio(&self) -> f64

Ratio of actual to estimated rows. Returns 1.0 when no estimate exists.

Trait Implementations

impl Clone for QueryStats

fn clone(&self) -> QueryStats

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for QueryStats

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

Formats the value using the given formatter.