RowReference

Struct RowReference 

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pub struct RowReference { /* private fields */ }
Expand description

A lightweight reference to a row in source data

Instead of cloning entire rows during query processing, RowReference stores just enough information to locate the row when materialization is needed.

§Memory Comparison

For a row with 10 columns averaging 32 bytes each:

  • Full Row: 320+ bytes (plus heap allocations for strings)
  • RowReference: 16 bytes (table_id + row_index)

This is 20x more memory efficient for intermediate results.

§Example

// Create references instead of copying rows
let refs: Vec<RowReference> = qualifying_indices
    .iter()
    .map(|&idx| RowReference::new(0, idx as u32))
    .collect();

// Only materialize at output boundary
let output_rows: Vec<Row> = refs
    .iter()
    .map(|r| source_tables[r.table_id()].row(r.row_index()))
    .collect();

Implementations§

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impl RowReference

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pub const fn new(table_id: u16, row_index: u32) -> Self

Create a new row reference

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pub const fn table_id(&self) -> u16

Get the table identifier

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pub const fn row_index(&self) -> u32

Get the row index within the table

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pub fn range(table_id: u16, start: u32, end: u32) -> Vec<Self>

Create a vector of row references for a range of rows

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pub fn from_selection(table_id: u16, indices: &[u32]) -> Vec<Self>

Create row references from a selection vector

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impl Clone for RowReference

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fn clone(&self) -> RowReference

Returns a duplicate of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for RowReference

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

Formats the value using the given formatter. Read more
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impl Hash for RowReference

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl PartialEq for RowReference

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

Tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

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

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impl Eq for RowReference

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impl StructuralPartialEq for RowReference

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Blanket Implementations§

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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<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
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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, U> Into<U> 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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impl<T> Pointable for T

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const ALIGN: usize

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<G1, G2> Within<G2> for G1
where G2: Contains<G1>,

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fn is_within(&self, b: &G2) -> bool

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impl<T> Allocation for T
where T: RefUnwindSafe + Send + Sync,