org.apache.calcite.plan.hep

Class HepRelVertex

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.plan.hep.HepRelVertex

All Implemented Interfaces:

Cloneable, RelOptNode, DelegatingMetadataRel, RelNode

public class HepRelVertex
extends AbstractRelNode
implements DelegatingMetadataRel

HepRelVertex wraps a real RelNode as a vertex in a DAG representing the entire query expression.

Nested Class Summary

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

RelNode.Context

Field Summary

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

digest, id, rowType, traitSet

Method Summary

Modifier and Type	Method and Description
@Nullable RelOptCost	computeSelfCost(RelOptPlanner planner, RelMetadataQuery mq) Returns the cost of this plan (not including children).
RelNode	copy(RelTraitSet traitSet, List<RelNode> inputs) Creates a copy of this relational expression, perhaps changing traits and inputs.
boolean	deepEquals(@Nullable Object obj) Equality check for RelNode digest.
int	deepHashCode() Compute hash code for RelNode digest.
protected RelDataType	deriveRowType()
double	estimateRowCount(RelMetadataQuery mq) Returns an estimate of the number of rows this relational expression will return.
void	explain(RelWriter pw) Describes the inputs and attributes of this relational expression.
RelNode	getCurrentRel() Returns current implementation chosen for this vertex.
String	getDigest() Returns a digest string of this RelNode.
RelNode	getMetadataDelegateRel() Returns RelNode for metadata.

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

accept, accept, childrenAccept, collectVariablesSet, collectVariablesUsed, equals, explainTerms, getCluster, getConvention, getCorrelVariable, getDescription, getExpectedInputRowType, getId, getInput, getInputs, 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

Method Detail

explain

public void explain(RelWriter pw)

Description copied from interface: RelNode

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

Specified by:

explain in interface RelNode

Overrides:

explain in class AbstractRelNode

Parameters:

pw - Plan writer

copy

public RelNode 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

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)

estimateRowCount

public double estimateRowCount(RelMetadataQuery mq)

Description copied from interface: RelNode

Returns an estimate of the number of rows this relational expression will return.

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

Specified by:

estimateRowCount in interface RelNode

Overrides:

estimateRowCount in class AbstractRelNode

Parameters:

mq - Metadata query

Returns:

Estimate of the number of rows this relational expression will return

deriveRowType

protected RelDataType deriveRowType()

Overrides:

deriveRowType in class AbstractRelNode

getCurrentRel

public RelNode getCurrentRel()

Returns current implementation chosen for this vertex.

getMetadataDelegateRel

public RelNode getMetadataDelegateRel()

Returns RelNode for metadata.

Specified by:

getMetadataDelegateRel in interface DelegatingMetadataRel

deepEquals

public boolean deepEquals(@Nullable Object obj)

Description copied from class: AbstractRelNode

Equality check for RelNode digest.

By default this method collects digest attributes from AbstractRelNode.explainTerms(RelWriter), then compares each attribute pair. This should work well for most cases. If this method is a performance bottleneck for your project, or the default behavior can't handle your scenario properly, you can choose to override this method and AbstractRelNode.deepHashCode(). See LogicalJoin as an example.

Specified by:

deepEquals in interface RelNode

Overrides:

deepEquals in class AbstractRelNode

Returns:

Whether the 2 RelNodes are equivalent or have the same digest.

See Also:

AbstractRelNode.deepHashCode()

deepHashCode

public int deepHashCode()

Description copied from class: AbstractRelNode

Compute hash code for RelNode digest.

Specified by:

deepHashCode in interface RelNode

Overrides:

deepHashCode in class AbstractRelNode

See Also:

RelNode.deepEquals(Object)

getDigest

public String getDigest()

Description copied from interface: RelNode

Returns a digest string of this RelNode.

Each call creates a new digest string, so don't forget to cache the result if necessary.

Specified by:

getDigest in interface RelOptNode

Specified by:

getDigest in interface RelNode

Overrides:

getDigest in class AbstractRelNode

Returns:

Digest string of this RelNode

See Also:

RelNode.getRelDigest()