org.apache.calcite.rel.core

Class SortExchange

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.SingleRel

org.apache.calcite.rel.core.Exchange

org.apache.calcite.rel.core.SortExchange

All Implemented Interfaces:

Cloneable, RelOptNode, RelNode

public abstract class SortExchange
extends Exchange

Relational expression that performs Exchange and Sort simultaneously.

Whereas a Sort produces output with a particular RelCollation and an Exchange produces output with a particular RelDistribution, the output of a SortExchange has both the required collation and distribution.

Several implementations of SortExchange are possible; the purpose of this base class allows rules to be written that apply to all of those implementations.

Field Summary

Fields

Modifier and Type	Field and Description
protected RelCollation	collation

Fields inherited from class org.apache.calcite.rel.core.Exchange

distribution

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

digest, id, rowType, traitSet

Constructor Summary

Constructors

Modifier	Constructor and Description
	SortExchange(RelInput input) Creates a SortExchange by parsing serialized output.
protected	SortExchange(RelOptCluster cluster, RelTraitSet traitSet, RelNode input, RelDistribution distribution, RelCollation collation) Creates a SortExchange.

Method Summary

Methods

Modifier and Type	Method and Description
SortExchange	copy(RelTraitSet traitSet, RelNode newInput, RelDistribution newDistribution)
abstract SortExchange	copy(RelTraitSet traitSet, RelNode newInput, RelDistribution newDistribution, RelCollation newCollation)
RelWriter	explainTerms(RelWriter pw) Describes the inputs and attributes of this relational expression.
RelCollation	getCollation() Returns the array of RelFieldCollations asked for by the sort specification, from most significant to least significant.

Methods inherited from class org.apache.calcite.rel.core.Exchange

computeSelfCost, copy, getDistribution

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

childrenAccept, deriveRowType, getInput, getInputs, getRows, replaceInput

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

accept, accept, collectVariablesSet, collectVariablesUsed, computeDigest, explain, getChildExps, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getQuery, getRelTypeName, getRowType, getTable, getTraitSet, getVariablesStopped, isDistinct, isKey, isValid, metadata, onRegister, recomputeDigest, register, sole, toString

Methods inherited from class java.lang.Object

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

Field Detail

collation

protected final RelCollation collation

Constructor Detail

SortExchange

protected SortExchange(RelOptCluster cluster,
            RelTraitSet traitSet,
            RelNode input,
            RelDistribution distribution,
            RelCollation collation)

Creates a SortExchange.

Parameters:

cluster - Cluster this relational expression belongs to

traitSet - Trait set

input - Input relational expression

distribution - Distribution specification

SortExchange

public SortExchange(RelInput input)

Creates a SortExchange by parsing serialized output.

Method Detail

copy

public final SortExchange copy(RelTraitSet traitSet,
                RelNode newInput,
                RelDistribution newDistribution)

Specified by:

copy in class Exchange

copy

public abstract SortExchange copy(RelTraitSet traitSet,
                RelNode newInput,
                RelDistribution newDistribution,
                RelCollation newCollation)

getCollation

public RelCollation getCollation()

Returns the array of RelFieldCollations asked for by the sort specification, from most significant to least significant.

See also RelMetadataQuery.collations(RelNode), which lists all known collations. For example, ORDER BY time_id might also be sorted by the_year, the_month because of a known monotonicity constraint among the columns. getCollation would return [time_id] and collations would return [ [time_id], [the_year, the_month] ].

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 RelWriterImpl.input(String, RelNode) and RelWriterImpl.item(String, Object) methods for each input and attribute.

Overrides:

explainTerms in class Exchange

Parameters:

pw - Plan writer

Returns:

Plan writer for fluent-explain pattern