Module canonicalize

Utility functions to transform parts of a single MirRelationExpr into canonical form.

Functions

canonicalize_equivalence_classes

Canonicalize only the equivalence classes of a join.

canonicalize_equivalences

Canonicalize equivalence classes of a join and expressions contained in them.

canonicalize_predicates

Canonicalize predicates of a filter.

compare_predicates 🔒

Comparison method for sorting predicates by their complexity, measured by the total number of non-literal expression nodes within the expression.

flat_map_modify 🔒

Applies a flat_map on a Vec, and overwrites the vec with the result.

get_canonicalizer_map

For each equivalence class, it finds the simplest expression, which will be the canonical one. Returns a Map that maps from each expression in each equivalence class to the canonical expression in the same equivalence class.

is_not_null 🔒

Returns the inner operand if the given predicate is an IS NOT NULL expression.

is_null_rejecting_predicate 🔒

Whether the given predicate evaluates to NULL when the given operand expression is NULL.

propagates_null_from_subexpression 🔒

rank_complexity 🔒

Gives a relative complexity ranking for an expression. Higher numbers mean greater complexity.

replace_subexpr_and_reduce 🔒

Replace any matching subexpressions in predicate, and if predicate has changed, reduce it. Return whether predicate has changed.