Module datafusion_physical_expr::equivalence

Structs

• ConstExpr
  A structure representing a expression known to be constant in a physical execution plan.
• EquivalenceClass
  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.
• EquivalenceGroup
  An EquivalenceGroup is a collection of EquivalenceClasses where each class represents a distinct equivalence class in a relation.
• EquivalenceProperties
  A EquivalenceProperties object stores useful information related to a schema. Currently, it keeps track of:
• OrderingEquivalenceClass
  An OrderingEquivalenceClass object keeps track of different alternative orderings than can describe a schema. For example, consider the following table:
• ProjectionMapping
  Stores the mapping between source expressions and target expressions for a projection.

Functions

• add_offset_to_expr
  Adds the offset value to Column indices inside expr. This function is generally used during the update of the right table schema in join operations.
• calculate_union
  Calculates the union (in the sense of UnionExec) EquivalenceProperties of the given EquivalenceProperties in eqps according to the given output schema (which need not be the same with those of lhs and rhs as details such as nullability may be different).
• collapse_lex_req
  This function constructs a duplicate-free LexOrderingReq by filtering out duplicate entries that have same physical expression inside. For example, vec![a Some(ASC), a Some(DESC)] collapses to vec![a Some(ASC)].
• join_equivalence_properties
  Calculate ordering equivalence properties for the given join operation.