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LogicalPlanVisitor

LogicalPlanVisitor is an abstraction of visitors that can traverse a logical query plan to compute result of type T (e.g., Statistics or unique Expressions).

Type Constructor

LogicalPlanVisitor[T] is a Scala type constructor with the type parameter T.

Visitor Design Pattern

LogicalPlanVisitor uses Visitor Design Pattern for traversing a logical query plan.

Contract (Subset)

visitAggregate

visitAggregate(
  p: Aggregate): T

Visits the given Aggregate logical operator

See:

Used when:

visitJoin

visitJoin(
  p: Join): T

Visits the given Join logical operator

See:

Used when:

  • LogicalPlanVisitor is requested to visit a Join logical operator

visitOffset

visitOffset(
  p: Offset): T

Visits the given Offset logical operator

See:

Used when:

  • LogicalPlanVisitor is requested to visit a Offset logical operator

Implementations

Visiting Logical Operator

visit(
  p: LogicalPlan): T

visit is the entry point (a dispatcher) to hand over the task of computing the statistics of the given logical operator to the corresponding handler methods.

visit is used when: