Module datafusion_optimizer::utils

Collection of utility functions that are leveraged by the query optimizer rules

Functions

add_filter

returns a new LogicalPlan that wraps plan in a LogicalPlan::Filter with its predicate be all predicates ANDed.

expr_sub_expressions

Returns all direct children Expressions of expr. E.g. if the expression is “(a + 1) + 1”, it returns [“a + 1”, “1”] (as Expr objects)

optimize_children

Convenience rule for writing optimizers: recursively invoke optimize on plan’s children and then return a node of the same type. Useful for optimizer rules which want to leave the type of plan unchanged but still apply to the children. This also handles the case when the plan is a LogicalPlan::Explain.

rewrite_expression

returns a new expression where the expressions in expr are replaced by the ones in expressions. This is used in conjunction with expr_expressions to re-write expressions.

split_conjunction

converts “A AND B AND C” => [A, B, C]