Struct CostSummary 

pub struct CostSummary {
    pub estimated_rows: u64,
    pub io_cost: u64,
    pub cpu_cost: u64,
    pub total_cost: f64,
}

Cost summary for the query.

Fields

estimated_rows: u64

Estimated total rows returned.

io_cost: u64

Estimated I/O operations (scans, lookups).

cpu_cost: u64

Estimated CPU cost (filter evaluations, comparisons).

total_cost: f64

Total weighted cost (io_cost * 10 + cpu_cost).

Implementations

impl CostSummary

pub fn new(estimated_rows: u64, io_cost: u64, cpu_cost: u64) -> Self

Create a new cost summary.

pub fn zero() -> Self

Create zero cost (for when statistics are unavailable).

Trait Implementations

impl Archive for CostSummary

where u64: Archive, f64: Archive,

const COPY_OPTIMIZATION: CopyOptimization<Self>

An optimization flag that allows the bytes of this type to be copied directly to a writer instead of calling serialize.

type Archived = ArchivedCostSummary

The archived representation of this type.

type Resolver = CostSummaryResolver

The resolver for this type. It must contain all the additional information from serializing needed to make the archived type from the normal type.

fn resolve(&self, resolver: Self::Resolver, out: Place<Self::Archived>)

Creates the archived version of this value at the given position and writes it to the given output.

impl Clone for CostSummary

fn clone(&self) -> CostSummary

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CostSummary

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for CostSummary

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<__D: Fallible + ?Sized> Deserialize<CostSummary, __D> for Archived<CostSummary>

where u64: Archive, <u64 as Archive>::Archived: Deserialize<u64, __D>, f64: Archive, <f64 as Archive>::Archived: Deserialize<f64, __D>,

fn deserialize( &self, deserializer: &mut __D, ) -> Result<CostSummary, <__D as Fallible>::Error>

Deserializes using the given deserializer

impl PartialEq for CostSummary

fn eq(&self, other: &CostSummary) -> 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<__S: Fallible + ?Sized> Serialize<__S> for CostSummary

where u64: Serialize<__S>, f64: Serialize<__S>,

fn serialize( &self, serializer: &mut __S, ) -> Result<<Self as Archive>::Resolver, <__S as Fallible>::Error>

Writes the dependencies for the object and returns a resolver that can create the archived type.

impl Serialize for CostSummary

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 CostSummary