Package org.apache.calcite.rel.core

Class Combine

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.core.Combine

All Implemented Interfaces:

Cloneable, RelOptNode, RelNode

public class Combine
extends AbstractRelNode

A relational operator that combines multiple relational expressions into a single root. This is used for multi-root optimization in the VolcanoPlanner.

Nested Class Summary

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

RelNode.Context

Field Summary

Fields

Modifier and Type	Field	Description
protected final com.google.common.collect.ImmutableList<RelNode>	inputs

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

digest, id, rowType, traitSet

Constructor Summary

Constructors

Constructor	Description
Combine(RelOptCluster cluster, RelTraitSet traitSet, List<RelNode> inputs)

Method Summary

Modifier and Type	Method	Description
RelOptCost	computeSelfCost(RelOptPlanner planner, RelMetadataQuery mq)	Returns the cost of this plan (not including children).
static Combine	create(RelOptCluster cluster, RelTraitSet traitSet, List<RelNode> inputs)	Creates a Combine.
protected RelDataType	deriveRowType()
RelWriter	explainTerms(RelWriter pw)	Describes the inputs and attributes of this relational expression.
List<RelNode>	getInputs()	Returns an array of this relational expression's inputs.

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

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

inputs

protected final com.google.common.collect.ImmutableList<RelNode> inputs

Constructor Details

Combine

public Combine(RelOptCluster cluster,
 RelTraitSet traitSet,
 List<RelNode> inputs)

Method Details

create

public static Combine create(RelOptCluster cluster,
 RelTraitSet traitSet,
 List<RelNode> inputs)

Creates a Combine.

getInputs

public List<RelNode> getInputs()

Description copied from interface: RelNode

Returns an array of this relational expression's inputs. If there are no inputs, returns an empty list, not null.

Specified by:

getInputs in interface RelNode

Specified by:

getInputs in interface RelOptNode

Overrides:

getInputs in class AbstractRelNode

Returns:

Array of this relational expression's inputs

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 AbstractRelNode

Parameters:

pw - Plan writer

Returns:

Plan writer for fluent-explain pattern

deriveRowType

protected RelDataType deriveRowType()

Overrides:

deriveRowType in class AbstractRelNode

computeSelfCost

public 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)