Struct datafusion_physical_expr::equivalence::OrderingEquivalenceProperties

pub struct OrderingEquivalenceProperties { /* private fields */ }

OrderingEquivalenceProperties keeps track of columns that describe the global ordering of the schema. These columns are not necessarily same; e.g.

┌-------┐
| a | b |
|---|---|
| 1 | 9 |
| 2 | 8 |
| 3 | 7 |
| 5 | 5 |
└---┴---┘

where both a ASC and b DESC can describe the table ordering. With OrderingEquivalenceProperties, we can keep track of these equivalences and treat a ASC and b DESC as the same ordering requirement.

Implementations

impl OrderingEquivalenceProperties

pub fn new(schema: SchemaRef) -> Self

Create an empty OrderingEquivalenceProperties

pub fn extend(&mut self, other: Option<OrderingEquivalentClass>)

Extends OrderingEquivalenceProperties by adding ordering inside the other to the self.oeq_class.

pub fn oeq_class(&self) -> Option<&OrderingEquivalentClass>

pub fn add_equal_conditions( &mut self, new_conditions: (&LexOrdering, &LexOrdering) )

Adds new equal conditions into the EquivalenceProperties. New equal conditions usually come from equality predicates in a join/filter.

pub fn with_constants(self, constants: Vec<Arc<dyn PhysicalExpr>>) -> Self

Add physical expression that have constant value to the self.constants

pub fn schema(&self) -> SchemaRef

pub fn normalize_sort_requirements( &self, sort_reqs: &[PhysicalSortRequirement] ) -> Vec<PhysicalSortRequirement>

This function normalizes sort_reqs by

• removing expressions that have constant value from requirement
• replacing sections that are in the self.oeq_class.others with self.oeq_class.head
• removing sections that satisfies global ordering that are in the post fix of requirement

pub fn satisfies_leading_ordering( &self, leading_ordering: &PhysicalSortExpr ) -> bool

Checks whether leading_ordering is contained in any of the ordering equivalence classes.

Trait Implementations

impl Clone for OrderingEquivalenceProperties

fn clone(&self) -> OrderingEquivalenceProperties

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for OrderingEquivalenceProperties

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

Formats the value using the given formatter.