Package org.apache.calcite.plan

Interface RelOptListener

All Superinterfaces:

EventListener

All Known Implementing Classes:

MulticastRelOptListener, RuleEventLogger, RuleMatchVisualizer

public interface RelOptListener
extends EventListener

RelOptListener defines an interface for listening to events which occur during the optimization process.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	RelOptListener.RelChosenEvent	Event indicating that a relational expression has been chosen.
static class	RelOptListener.RelDiscardedEvent	Event indicating that a relational expression has been discarded.
static class	RelOptListener.RelEquivalenceEvent	Event indicating that a relational expression has been found to be equivalent to an equivalence class.
static class	RelOptListener.RelEvent	Event class for abstract event dealing with a relational expression.
static class	RelOptListener.RuleAttemptedEvent	Event indicating that a planner rule has been attempted.
static class	RelOptListener.RuleEvent	Event indicating that a planner rule has fired.
static class	RelOptListener.RuleProductionEvent	Event indicating that a planner rule has produced a result.

Method Summary

Modifier and Type	Method	Description
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.
void	relDiscarded(RelOptListener.RelDiscardedEvent event)	Notifies this listener that a relational expression is no longer of interest to the planner.
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.
void	ruleAttempted(RelOptListener.RuleAttemptedEvent event)	Notifies this listener that an optimizer rule is being applied to a particular relational expression.
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).

Method Details

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