Struct EquivalenceClass

pub struct EquivalenceClass { /* private fields */ }

An EquivalenceClass is a set of Arc<dyn PhysicalExpr>s that are known to have the same value for all tuples in a relation. These are generated by equality predicates (e.g. a = b), typically equi-join conditions and equality conditions in filters.

Two EquivalenceClasses are equal if they contains the same expressions in without any ordering.

Implementations

impl EquivalenceClass

pub fn new( exprs: impl IntoIterator<Item = Arc<dyn PhysicalExpr>>, ) -> EquivalenceClass

pub fn canonical_expr(&self) -> Option<&Arc<dyn PhysicalExpr>>

Return the “canonical” expression for this class (the first element) if non-empty.

pub fn push(&mut self, expr: Arc<dyn PhysicalExpr>)

Insert the expression into this class, meaning it is known to be equal to all other expressions in this class.

pub fn extend(&mut self, other: EquivalenceClass)

Inserts all the expressions from other into this class.

pub fn contains_any(&self, other: &EquivalenceClass) -> bool

Returns whether this equivalence class has any entries in common with other.

pub fn is_trivial(&self) -> bool

Returns whether this equivalence class is trivial, meaning that it is either empty, or contains a single expression that is not a constant. Such classes are not useful, and can be removed from equivalence groups.

pub fn try_with_offset( &self, offset: isize, ) -> Result<EquivalenceClass, DataFusionError>

Adds the given offset to all columns in the expressions inside this class. This is used when schemas are appended, e.g. in joins.

Methods from Deref<Target = IndexSet<Arc<dyn PhysicalExpr>>>

pub fn capacity(&self) -> usize

Return the number of elements the set can hold without reallocating.

This number is a lower bound; the set might be able to hold more, but is guaranteed to be able to hold at least this many.

Computes in O(1) time.

pub fn hasher(&self) -> &S

Return a reference to the set’s BuildHasher.

pub fn len(&self) -> usize

Return the number of elements in the set.

Computes in O(1) time.

pub fn is_empty(&self) -> bool

Returns true if the set contains no elements.

Computes in O(1) time.

pub fn iter(&self) -> Iter<'_, T>

Return an iterator over the values of the set, in their order

pub fn difference<'a, S2>( &'a self, other: &'a IndexSet<T, S2>, ) -> Difference<'a, T, S2>

where S2: BuildHasher,

Return an iterator over the values that are in self but not other.

Values are produced in the same order that they appear in self.

pub fn symmetric_difference<'a, S2>( &'a self, other: &'a IndexSet<T, S2>, ) -> SymmetricDifference<'a, T, S, S2>

where S2: BuildHasher,

Return an iterator over the values that are in self or other, but not in both.

Values from self are produced in their original order, followed by values from other in their original order.

pub fn intersection<'a, S2>( &'a self, other: &'a IndexSet<T, S2>, ) -> Intersection<'a, T, S2>

where S2: BuildHasher,

Return an iterator over the values that are in both self and other.

Values are produced in the same order that they appear in self.

pub fn union<'a, S2>(&'a self, other: &'a IndexSet<T, S2>) -> Union<'a, T, S>

where S2: BuildHasher,

Return an iterator over all values that are in self or other.

Values from self are produced in their original order, followed by values that are unique to other in their original order.

pub fn contains<Q>(&self, value: &Q) -> bool

where Q: Hash + Equivalent<T> + ?Sized,

Return true if an equivalent to value exists in the set.

Computes in O(1) time (average).

pub fn get<Q>(&self, value: &Q) -> Option<&T>

where Q: Hash + Equivalent<T> + ?Sized,

Return a reference to the value stored in the set, if it is present, else None.

Computes in O(1) time (average).

pub fn get_full<Q>(&self, value: &Q) -> Option<(usize, &T)>

where Q: Hash + Equivalent<T> + ?Sized,

Return item index and value

pub fn get_index_of<Q>(&self, value: &Q) -> Option<usize>

where Q: Hash + Equivalent<T> + ?Sized,

Return item index, if it exists in the set

Computes in O(1) time (average).

pub fn binary_search(&self, x: &T) -> Result<usize, usize>

where T: Ord,

Search over a sorted set for a value.

Returns the position where that value is present, or the position where it can be inserted to maintain the sort. See slice::binary_search for more details.

Computes in O(log(n)) time, which is notably less scalable than looking the value up using get_index_of, but this can also position missing values.

pub fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize>

where F: FnMut(&'a T) -> Ordering,

Search over a sorted set with a comparator function.

Returns the position where that value is present, or the position where it can be inserted to maintain the sort. See slice::binary_search_by for more details.

Computes in O(log(n)) time.

pub fn binary_search_by_key<'a, B, F>( &'a self, b: &B, f: F, ) -> Result<usize, usize>

where F: FnMut(&'a T) -> B, B: Ord,

Search over a sorted set with an extraction function.

Returns the position where that value is present, or the position where it can be inserted to maintain the sort. See slice::binary_search_by_key for more details.

Computes in O(log(n)) time.

pub fn partition_point<P>(&self, pred: P) -> usize

where P: FnMut(&T) -> bool,

Returns the index of the partition point of a sorted set according to the given predicate (the index of the first element of the second partition).

See slice::partition_point for more details.

Computes in O(log(n)) time.

pub fn as_slice(&self) -> &Slice<T>

Returns a slice of all the values in the set.

Computes in O(1) time.

pub fn get_index(&self, index: usize) -> Option<&T>

Get a value by index

Valid indices are 0 <= index < self.len().

Computes in O(1) time.

pub fn get_range<R>(&self, range: R) -> Option<&Slice<T>>

where R: RangeBounds<usize>,

Returns a slice of values in the given range of indices.

Valid indices are 0 <= index < self.len().

Computes in O(1) time.

pub fn first(&self) -> Option<&T>

Get the first value

Computes in O(1) time.

pub fn last(&self) -> Option<&T>

Get the last value

Computes in O(1) time.

pub fn is_disjoint<S2>(&self, other: &IndexSet<T, S2>) -> bool

where S2: BuildHasher,

Returns true if self has no elements in common with other.

pub fn is_subset<S2>(&self, other: &IndexSet<T, S2>) -> bool

where S2: BuildHasher,

Returns true if all elements of self are contained in other.

pub fn is_superset<S2>(&self, other: &IndexSet<T, S2>) -> bool

where S2: BuildHasher,

Returns true if all elements of other are contained in self.

Trait Implementations

impl Clone for EquivalenceClass

fn clone(&self) -> EquivalenceClass

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EquivalenceClass

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

Formats the value using the given formatter.

impl Default for EquivalenceClass

fn default() -> EquivalenceClass

Returns the “default value” for a type.

impl Deref for EquivalenceClass

type Target = IndexSet<Arc<dyn PhysicalExpr>>

The resulting type after dereferencing.

fn deref(&self) -> &<EquivalenceClass as Deref>::Target

Dereferences the value.

impl Display for EquivalenceClass

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

Formats the value using the given formatter.

impl From<EquivalenceClass> for Vec<Arc<dyn PhysicalExpr>>

fn from(cls: EquivalenceClass) -> Vec<Arc<dyn PhysicalExpr>>

Converts to this type from the input type.

impl IntoIterator for EquivalenceClass

type Item = Arc<dyn PhysicalExpr>

The type of the elements being iterated over.

type IntoIter = <IndexSet<<EquivalenceClass as IntoIterator>::Item> as IntoIterator>::IntoIter

Which kind of iterator are we turning this into?

fn into_iter(self) -> <EquivalenceClass as IntoIterator>::IntoIter

Creates an iterator from a value.

impl PartialEq for EquivalenceClass

fn eq(&self, other: &EquivalenceClass) -> 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 Eq for EquivalenceClass

impl StructuralPartialEq for EquivalenceClass