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.
• 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.