Struct Observation 

pub struct Observation {
    pub template_hash: String,
    pub plan_fingerprint: String,
    pub est_rows: u64,
    pub actual_rows: u64,
    pub latency_ms: Option<f64>,
}

A single observation captured at query end.

Fields

template_hash: String

plan_fingerprint: String

est_rows: u64

actual_rows: u64

latency_ms: Option<f64>

Implementations

impl Observation

pub fn q_error(&self) -> f64

Multiplicative q-error: max(actual/est, est/actual). Returns f64::INFINITY if either is 0.

Examples

use samkhya_core::feedback::Observation;

// 10× underestimate: est=10, actual=100 → q-error = 10.
let obs = Observation {
    template_hash: "t".into(),
    plan_fingerprint: "p".into(),
    est_rows: 10,
    actual_rows: 100,
    latency_ms: None,
};
assert!((obs.q_error() - 10.0).abs() < 1e-9);

Trait Implementations

impl Clone for Observation

fn clone(&self) -> Observation

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Observation

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Observation

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Observation

fn eq(&self, other: &Observation) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Observation

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Observation