Interface RelOptListener

  • All Superinterfaces:
    java.util.EventListener
    All Known Implementing Classes:
    MulticastRelOptListener

    public interface RelOptListener
    extends java.util.EventListener
    RelOptListener defines an interface for listening to events which occur during the optimization process.
    • Method Detail

      • relEquivalenceFound

        void relEquivalenceFound​(RelOptListener.RelEquivalenceEvent event)
        Notifies this listener that a relational expression has been registered with a particular equivalence class after an equivalence has been either detected or asserted. Equivalence classes may be either logical (all expressions which yield the same result set) or physical (all expressions which yield the same result set with a particular calling convention).
        Parameters:
        event - details about the event
      • ruleAttempted

        void ruleAttempted​(RelOptListener.RuleAttemptedEvent event)
        Notifies this listener that an optimizer rule is being applied to a particular relational expression. This rule is called twice; once before the rule is invoked, and once after. Note that the rel attribute of the event is always the old expression.
        Parameters:
        event - details about the event
      • ruleProductionSucceeded

        void ruleProductionSucceeded​(RelOptListener.RuleProductionEvent event)
        Notifies this listener that an optimizer rule has been successfully applied to a particular relational expression, resulting in a new equivalent expression (relEquivalenceFound will also be called unless the new expression is identical to an existing one). This rule is called twice; once before registration of the new rel, and once after. Note that the rel attribute of the event is always the new expression; to get the old expression, use event.getRuleCall().rels[0].
        Parameters:
        event - details about the event
      • relDiscarded

        void relDiscarded​(RelOptListener.RelDiscardedEvent event)
        Notifies this listener that a relational expression is no longer of interest to the planner.
        Parameters:
        event - details about the event
      • relChosen

        void relChosen​(RelOptListener.RelChosenEvent event)
        Notifies this listener that a relational expression has been chosen as part of the final implementation of the query plan. After the plan is complete, this is called one more time with null for the rel.
        Parameters:
        event - details about the event