Struct CardinalityEstimate

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pub struct CardinalityEstimate {
    pub rows: f64,
    pub selectivity: f64,
    pub confidence: f64,
}

Expand description

Cardinality estimate for a query result

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§rows: f64

Estimated row/record count

§selectivity: f64

Selectivity factor (0.0 - 1.0)

§confidence: f64

Confidence in the estimate (0.0 - 1.0)

Implementations§

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impl CardinalityEstimate

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pub fn new(rows: f64, selectivity: f64) -> CardinalityEstimate

Create a new cardinality estimate

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pub fn full_scan(table_size: f64) -> CardinalityEstimate

Full table scan estimate

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pub fn with_filter(self, filter_selectivity: f64) -> CardinalityEstimate

Apply a filter to reduce cardinality

Trait Implementations§

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impl Clone for CardinalityEstimate

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fn clone(&self) -> CardinalityEstimate

Returns a duplicate of the value. Read more

1.0.0 (const: unstable) · Source§

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

Performs copy-assignment from source. Read more

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impl Debug for CardinalityEstimate

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

Formats the value using the given formatter. Read more

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impl Default for CardinalityEstimate

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fn default() -> CardinalityEstimate

Returns the “default value” for a type. Read more

Auto Trait Implementations§

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impl UnwindSafe for CardinalityEstimate

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)

Performs copy-assignment from self to dest. Read more

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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> FromRef<T> for T
where T: Clone,

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fn from_ref(input: &T) -> T

Converts to this type from a reference to the input type.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more

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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more

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impl<T, U> Into for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more

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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more

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