Package org.apache.calcite.rel

Class RelDistributionTraitDef

java.lang.Object

org.apache.calcite.plan.RelTraitDef<RelDistribution>

org.apache.calcite.rel.RelDistributionTraitDef

public class RelDistributionTraitDef
extends RelTraitDef<RelDistribution>

Definition of the distribution trait.

Distribution is a physical property (i.e. a trait) because it can be changed without loss of information. The converter to do this is the Exchange operator.

Field Summary

Fields

Modifier and Type	Field	Description
static final RelDistributionTraitDef	INSTANCE

Method Summary

Modifier and Type	Method	Description
boolean	canConvert(RelOptPlanner planner, RelDistribution fromTrait, RelDistribution toTrait)	Tests whether the given RelTrait can be converted to another RelTrait.
@Nullable RelNode	convert(RelOptPlanner planner, RelNode rel, RelDistribution toDistribution, boolean allowInfiniteCostConverters)	Converts the given RelNode to the given RelTrait.
RelDistribution	getDefault()	Returns the default member of this trait.
String	getSimpleName()	Returns a simple name for this RelTraitDef (for use in RelNode.explain(org.apache.calcite.rel.RelWriter)).
Class<RelDistribution>	getTraitClass()	Returns the specific RelTrait type associated with this RelTraitDef.

Methods inherited from class org.apache.calcite.plan.RelTraitDef

canonize, deregisterConverterRule, multiple, registerConverterRule

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

INSTANCE

public static final RelDistributionTraitDef INSTANCE

Method Details

getTraitClass

public Class<RelDistribution> getTraitClass()

Description copied from class: RelTraitDef

Returns the specific RelTrait type associated with this RelTraitDef.

Specified by:

getTraitClass in class RelTraitDef<RelDistribution>

getSimpleName

public String getSimpleName()

Description copied from class: RelTraitDef

Returns a simple name for this RelTraitDef (for use in RelNode.explain(org.apache.calcite.rel.RelWriter)).

Specified by:

getSimpleName in class RelTraitDef<RelDistribution>

getDefault

public RelDistribution getDefault()

Description copied from class: RelTraitDef

Returns the default member of this trait.

Specified by:

getDefault in class RelTraitDef<RelDistribution>

convert

public @Nullable RelNode convert(RelOptPlanner planner,
 RelNode rel,
 RelDistribution toDistribution,
 boolean allowInfiniteCostConverters)

Description copied from class: RelTraitDef

Converts the given RelNode to the given RelTrait.

Specified by:

convert in class RelTraitDef<RelDistribution>

Parameters:

planner - the planner requesting the conversion

rel - RelNode to convert

toDistribution - RelTrait to convert to

allowInfiniteCostConverters - flag indicating whether infinite cost converters are allowed

Returns:

a converted RelNode or null if conversion is not possible

canConvert

public boolean canConvert(RelOptPlanner planner,
 RelDistribution fromTrait,
 RelDistribution toTrait)

Description copied from class: RelTraitDef

Tests whether the given RelTrait can be converted to another RelTrait.

Specified by:

canConvert in class RelTraitDef<RelDistribution>

Parameters:

planner - the planner requesting the conversion test

fromTrait - the RelTrait to convert from

toTrait - the RelTrait to convert to

Returns:

true if fromTrait can be converted to toTrait