Package org.apache.calcite.rel.core

Class Exchange

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.SingleRel

org.apache.calcite.rel.core.Exchange

All Implemented Interfaces:

Cloneable, RelOptNode, RelNode

Direct Known Subclasses:

LogicalExchange, SortExchange

public abstract class Exchange
extends SingleRel

Relational expression that imposes a particular distribution on its input without otherwise changing its content.

See Also:

• SortExchange

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.calcite.rel.RelNode

RelNode.Context

Field Summary

Fields

Modifier and Type	Field	Description
final RelDistribution	distribution

Fields inherited from class org.apache.calcite.rel.SingleRel

input

Fields inherited from class org.apache.calcite.rel.AbstractRelNode

digest, id, rowType, traitSet

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Exchange(RelOptCluster cluster, RelTraitSet traitSet, RelNode input, RelDistribution distribution)	Creates an Exchange.
protected	Exchange(RelInput input)	Creates an Exchange by parsing serialized output.

Method Summary

Modifier and Type	Method	Description
@Nullable RelOptCost	computeSelfCost(RelOptPlanner planner, RelMetadataQuery mq)	Returns the cost of this plan (not including children).
final Exchange	copy(RelTraitSet traitSet, List<RelNode> inputs)	Creates a copy of this relational expression, perhaps changing traits and inputs.
abstract Exchange	copy(RelTraitSet traitSet, RelNode newInput, RelDistribution newDistribution)
RelWriter	explainTerms(RelWriter pw)	Describes the inputs and attributes of this relational expression.
RelDistribution	getDistribution()	Returns the distribution of the rows returned by this Exchange.

Methods inherited from class org.apache.calcite.rel.SingleRel

childrenAccept, deriveRowType, estimateRowCount, getInput, getInputs, replaceInput

Methods inherited from class org.apache.calcite.rel.AbstractRelNode

accept, accept, collectVariablesSet, collectVariablesUsed, deepEquals, deepHashCode, equals, explain, getCluster, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getRelDigest, getRelTypeName, getRowType, getTable, getTraitSet, getVariablesSet, hashCode, isEnforcer, isValid, metadata, onRegister, recomputeDigest, register, sole, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.calcite.rel.RelNode

explain, fieldIsNullable, stripped

Field Details

distribution

public final RelDistribution distribution

Constructor Details

Exchange

protected Exchange(RelOptCluster cluster,
 RelTraitSet traitSet,
 RelNode input,
 RelDistribution distribution)

Creates an Exchange.

Parameters:

cluster - Cluster this relational expression belongs to

traitSet - Trait set

input - Input relational expression

distribution - Distribution specification

Exchange

protected Exchange(RelInput input)

Creates an Exchange by parsing serialized output.

Method Details

copy

public final Exchange copy(RelTraitSet traitSet,
 List<RelNode> inputs)

Description copied from interface: RelNode

Creates a copy of this relational expression, perhaps changing traits and inputs.

Sub-classes with other important attributes are encouraged to create variants of this method with more parameters.

Specified by:

copy in interface RelNode

Overrides:

copy in class AbstractRelNode

Parameters:

traitSet - Trait set

inputs - Inputs

Returns:

Copy of this relational expression, substituting traits and inputs

copy

public abstract Exchange copy(RelTraitSet traitSet,
 RelNode newInput,
 RelDistribution newDistribution)

getDistribution

public RelDistribution getDistribution()

Returns the distribution of the rows returned by this Exchange.

computeSelfCost

public @Nullable RelOptCost computeSelfCost(RelOptPlanner planner,
 RelMetadataQuery mq)

Description copied from interface: RelNode

Returns the cost of this plan (not including children). The base implementation throws an error; derived classes should override.

NOTE jvs 29-Mar-2006: Don't call this method directly. Instead, use RelMetadataQuery.getNonCumulativeCost(org.apache.calcite.rel.RelNode), which gives plugins a chance to override the rel's default ideas about cost.

Specified by:

computeSelfCost in interface RelNode

Overrides:

computeSelfCost in class AbstractRelNode

Parameters:

planner - Planner for cost calculation

mq - Metadata query

Returns:

Cost of this plan (not including children)

explainTerms

public RelWriter explainTerms(RelWriter pw)

Description copied from class: AbstractRelNode

Describes the inputs and attributes of this relational expression. Each node should call super.explainTerms, then call the RelWriter.input(String, RelNode) and RelWriter.item(String, Object) methods for each input and attribute.

Overrides:

explainTerms in class SingleRel

Parameters:

pw - Plan writer

Returns:

Plan writer for fluent-explain pattern