org.apache.calcite.rel

Class AbstractRelNode

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

All Implemented Interfaces:

Cloneable, RelOptNode, RelNode

Direct Known Subclasses:

BiRel, HepRelVertex, MultiJoin, RelSubset, SetOp, SingleRel, TableFunctionScan, TableScan, Values

public abstract class AbstractRelNode
extends Object
implements RelNode

Base class for every relational expression (RelNode).

Nested Class Summary

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

RelNode.Context

Field Summary

Fields

Modifier and Type	Field and Description
protected RelDigest	digest The digest that uniquely identifies the node.
protected int	id Unique id of this object, for debugging.
protected @MonotonicNonNull RelDataType	rowType Cached type of this relational expression.
protected RelTraitSet	traitSet RelTraitSet that describes the traits of this RelNode.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractRelNode(RelOptCluster cluster, RelTraitSet traitSet) Creates an AbstractRelNode.

Method Summary

Modifier and Type	Method and Description
RelNode	accept(RelShuttle shuttle) Accepts a visit from a shuttle.
RelNode	accept(RexShuttle shuttle) Accepts a visit from a shuttle.
void	childrenAccept(RelVisitor visitor) Interacts with the RelVisitor in a visitor pattern to traverse the tree of relational expressions.
void	collectVariablesSet(Set<CorrelationId> variableSet) Collects variables set by this expression.
void	collectVariablesUsed(Set<CorrelationId> variableSet) Collects variables known to be used by this expression or its descendants.
@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()
boolean	equals(@Nullable Object obj)
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.
RelWriter	explainTerms(RelWriter pw) Describes the inputs and attributes of this relational expression.
RelOptCluster	getCluster() Returns the cluster this relational expression belongs to.
@Nullable Convention	getConvention() Return the CallingConvention trait from this RelNode's trait set.
@Nullable String	getCorrelVariable() Returns the name of the variable which is to be implicitly set at runtime each time a row is returned from the first input of this relational expression; or null if there is no variable.
String	getDescription() Deprecated.
String	getDigest() Returns a digest string of this RelNode.
RelDataType	getExpectedInputRowType(int ordinalInParent) Returns the type of the rows expected for an input.
int	getId() Returns the ID of this relational expression, unique among all relational expressions created since the server was started.
RelNode	getInput(int i) Returns the ith input relational expression.
List<RelNode>	getInputs() Returns an array of this relational expression's inputs.
RelDigest	getRelDigest() Returns a digest of this RelNode.
String	getRelTypeName() Returns the name of this relational expression's class, sans package name, for use in explain.
RelDataType	getRowType() Returns the type of the rows returned by this relational expression.
@Nullable RelOptTable	getTable() If this relational expression represents an access to a table, returns that table, otherwise returns null.
RelTraitSet	getTraitSet() Retrieves this RelNode's traits.
Set<CorrelationId>	getVariablesSet() Returns the variables that are set in this relational expression but also used and therefore not available to parents of this relational expression.
int	hashCode()
boolean	isEnforcer() Indicates whether it is an enforcer operator, e.g.
boolean	isValid(Litmus litmus, @Nullable RelNode.Context context) Returns whether this relational expression is valid.
<M extends Metadata> M	metadata(Class<M> metadataClass, RelMetadataQuery mq) Deprecated.
RelNode	onRegister(RelOptPlanner planner) Receives notification that this expression is about to be registered.
void	recomputeDigest() Recomputes the digest.
void	register(RelOptPlanner planner) Registers any special rules specific to this kind of relational expression.
void	replaceInput(int ordinalInParent, RelNode p) Replaces the ordinalInParentth input.
protected static <T> T	sole(List<T> collection)
String	toString() Description; consists of id plus digest.

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

Field Detail

rowType

protected @MonotonicNonNull RelDataType rowType

Cached type of this relational expression.

digest

@API(since="1.24",
     status=INTERNAL)
protected RelDigest digest

The digest that uniquely identifies the node.

id

protected final int id

Unique id of this object, for debugging.

traitSet

protected RelTraitSet traitSet

RelTraitSet that describes the traits of this RelNode.

Constructor Detail

AbstractRelNode

protected AbstractRelNode(RelOptCluster cluster,
                          RelTraitSet traitSet)

Creates an AbstractRelNode.

Method Detail

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

Parameters:

traitSet - Trait set

inputs - Inputs

Returns:

Copy of this relational expression, substituting traits and inputs

sole

protected static <T> T sole(List<T> collection)

getCluster

public final RelOptCluster getCluster()

Description copied from interface: RelOptNode

Returns the cluster this relational expression belongs to.

Specified by:

getCluster in interface RelOptNode

Returns:

cluster

getConvention

@Pure
public final @Nullable Convention getConvention(@UnknownInitialization AbstractRelNode this)

Description copied from interface: RelNode

Return the CallingConvention trait from this RelNode's trait set.

Specified by:

getConvention in interface RelNode

Returns:

this RelNode's CallingConvention

getTraitSet

public RelTraitSet getTraitSet()

Description copied from interface: RelOptNode

Retrieves this RelNode's traits. Note that although the RelTraitSet returned is modifiable, it must not be modified during optimization. It is legal to modify the traits of a RelNode before or after optimization, although doing so could render a tree of RelNodes unimplementable. If a RelNode's traits need to be modified during optimization, clone the RelNode and change the clone's traits.

Specified by:

getTraitSet in interface RelOptNode

Returns:

this RelNode's trait set

getCorrelVariable

public @Nullable String getCorrelVariable()

Description copied from interface: RelNode

Returns the name of the variable which is to be implicitly set at runtime each time a row is returned from the first input of this relational expression; or null if there is no variable.

Specified by:

getCorrelVariable in interface RelNode

Returns:

Name of correlating variable, or null

getId

public int getId()

Description copied from interface: RelOptNode

Returns the ID of this relational expression, unique among all relational expressions created since the server was started.

Specified by:

getId in interface RelOptNode

Returns:

Unique ID

getInput

public RelNode getInput(int i)

Description copied from interface: RelNode

Returns the i^th input relational expression.

Specified by:

getInput in interface RelNode

Parameters:

i - Ordinal of input

Returns:

i^th input

register

public void register(RelOptPlanner planner)

Description copied from interface: RelNode

Registers any special rules specific to this kind of relational expression.

The planner calls this method this first time that it sees a relational expression of this class. The derived class should call RelOptPlanner.addRule(org.apache.calcite.plan.RelOptRule) for each rule, and then call super.register.

Specified by:

register in interface RelNode

Parameters:

planner - Planner to be used to register additional relational expressions

getRelTypeName

public String getRelTypeName()

Description copied from interface: RelNode

Returns the name of this relational expression's class, sans package name, for use in explain. For example, for a org.apache.calcite.rel.ArrayRel.ArrayReader, this method returns "ArrayReader".

Specified by:

getRelTypeName in interface RelNode

Returns:

Name of this relational expression's class, sans package name, for use in explain

isValid

public boolean isValid(Litmus litmus,
                       @Nullable RelNode.Context context)

Description copied from interface: RelNode

Returns whether this relational expression is valid.

If assertions are enabled, this method is typically called with litmus = THROW, as follows:

assert rel.isValid(Litmus.THROW)

This signals that the method can throw an AssertionError if it is not valid.

Specified by:

isValid in interface RelNode

Parameters:

litmus - What to do if invalid

context - Context for validity checking

Returns:

Whether relational expression is valid

getRowType

public final RelDataType getRowType()

Description copied from interface: RelNode

Returns the type of the rows returned by this relational expression.

Specified by:

getRowType in interface RelOptNode

Specified by:

getRowType in interface RelNode

deriveRowType

protected RelDataType deriveRowType()

getExpectedInputRowType

public RelDataType getExpectedInputRowType(int ordinalInParent)

Description copied from interface: RelNode

Returns the type of the rows expected for an input. Defaults to RelNode.getRowType().

Specified by:

getExpectedInputRowType in interface RelNode

Parameters:

ordinalInParent - input's 0-based ordinal with respect to this parent rel

Returns:

expected row type

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 RelOptNode

Specified by:

getInputs in interface RelNode

Returns:

Array of this relational expression's inputs

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

Parameters:

mq - Metadata query

Returns:

Estimate of the number of rows this relational expression will return

getVariablesSet

public Set<CorrelationId> getVariablesSet()

Description copied from interface: RelNode

Returns the variables that are set in this relational expression but also used and therefore not available to parents of this relational expression.

Note: only Correlate should set variables.

Specified by:

getVariablesSet in interface RelNode

Returns:

Names of variables which are set in this relational expression

collectVariablesUsed

public void collectVariablesUsed(Set<CorrelationId> variableSet)

Description copied from interface: RelNode

Collects variables known to be used by this expression or its descendants. By default, no such information is available and must be derived by analyzing sub-expressions, but some optimizer implementations may insert special expressions which remember such information.

Specified by:

collectVariablesUsed in interface RelNode

Parameters:

variableSet - receives variables used

isEnforcer

public boolean isEnforcer()

Description copied from interface: RelNode

Indicates whether it is an enforcer operator, e.g. PhysicalSort, PhysicalHashDistribute, etc. As an enforcer, the operator must be created only when required traitSet is not satisfied by its input.

Specified by:

isEnforcer in interface RelNode

Returns:

Whether it is an enforcer operator

collectVariablesSet

public void collectVariablesSet(Set<CorrelationId> variableSet)

Description copied from interface: RelNode

Collects variables set by this expression. TODO: is this required?

Specified by:

collectVariablesSet in interface RelNode

Parameters:

variableSet - receives variables known to be set by

childrenAccept

public void childrenAccept(RelVisitor visitor)

Description copied from interface: RelNode

Interacts with the RelVisitor in a visitor pattern to traverse the tree of relational expressions.

Specified by:

childrenAccept in interface RelNode

Parameters:

visitor - Visitor that will traverse the tree of relational expressions

accept

public RelNode accept(RelShuttle shuttle)

Description copied from interface: RelNode

Accepts a visit from a shuttle.

Specified by:

accept in interface RelNode

Parameters:

shuttle - Shuttle

Returns:

A copy of this node incorporating changes made by the shuttle to this node's children

accept

public RelNode accept(RexShuttle shuttle)

Description copied from interface: RelNode

Accepts a visit from a shuttle. If the shuttle updates expression, then a copy of the relation should be created. This new relation might have a different row-type.

Specified by:

accept in interface RelNode

Parameters:

shuttle - Shuttle

Returns:

A copy of this node incorporating changes made by the shuttle to this node's children

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

Parameters:

planner - Planner for cost calculation

mq - Metadata query

Returns:

Cost of this plan (not including children)

metadata

@Deprecated
public final <M extends Metadata> M metadata(Class<M> metadataClass,
                                                         RelMetadataQuery mq)

Deprecated.

Description copied from interface: RelNode

Returns a metadata interface.

Specified by:

metadata in interface RelNode

Type Parameters:

M - Type of metadata being requested

Parameters:

metadataClass - Metadata interface

mq - Metadata query

Returns:

Metadata object that supplies the desired metadata (never null, although if the information is not present the metadata object may return null from all methods)

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

Parameters:

pw - Plan writer

explainTerms

public RelWriter explainTerms(RelWriter pw)

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.

Parameters:

pw - Plan writer

Returns:

Plan writer for fluent-explain pattern

onRegister

public RelNode onRegister(RelOptPlanner planner)

Description copied from interface: RelNode

Receives notification that this expression is about to be registered. The implementation of this method must at least register all child expressions.

Specified by:

onRegister in interface RelNode

Parameters:

planner - Planner that plans this relational node

Returns:

Relational expression that should be used by the planner

recomputeDigest

public void recomputeDigest()

Description copied from interface: RelNode

Recomputes the digest.

INTERNAL USE ONLY. For use by the planner.

Specified by:

recomputeDigest in interface RelNode

See Also:

RelNode.getDigest()

replaceInput

public void replaceInput(int ordinalInParent,
                         RelNode p)

Description copied from interface: RelNode

Replaces the ordinalInParent^th input. You must override this method if you override RelNode.getInputs().

Specified by:

replaceInput in interface RelNode

Parameters:

ordinalInParent - Position of the child input, 0 is the first

p - New node that should be put at position ordinalInParent

toString

public String toString()

Description; consists of id plus digest.

Overrides:

toString in class Object

getDescription

@Deprecated
public final String getDescription()

Deprecated.

Description copied from interface: RelOptNode

Returns a string which describes the relational expression and, unlike RelOptNode.getDigest(), also includes the identity. Typically returns "rel#{id}:{digest}".

Specified by:

getDescription in interface RelOptNode

Returns:

String which describes the relational expression and, unlike RelOptNode.getDigest(), also includes the identity

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

Returns:

Digest string of this RelNode

See Also:

RelNode.getRelDigest()

getRelDigest

public final RelDigest getRelDigest()

Description copied from interface: RelNode

Returns a digest of this RelNode.

INTERNAL USE ONLY. For use by the planner.

Specified by:

getRelDigest in interface RelNode

Returns:

Digest of this RelNode

See Also:

RelNode.getDigest()

getTable

public @Nullable RelOptTable getTable()

Description copied from interface: RelNode

If this relational expression represents an access to a table, returns that table, otherwise returns null.

Specified by:

getTable in interface RelNode

Returns:

If this relational expression represents an access to a table, returns that table, otherwise returns null

equals

public final boolean equals(@Nullable Object obj)

This method (and hashCode() is intentionally final. We do not want sub-classes of RelNode to redefine identity. Various algorithms (e.g. visitors, planner) can define the identity as meets their needs.

Overrides:

equals in class Object

hashCode

public final int hashCode()

This method (and equals(java.lang.Object) is intentionally final. We do not want sub-classes of RelNode to redefine identity. Various algorithms (e.g. visitors, planner) can define the identity as meets their needs.

Overrides:

hashCode in class Object

deepEquals

@API(since="1.25",
     status=MAINTAINED)
public boolean deepEquals(@Nullable Object obj)

Equality check for RelNode digest.

By default this method collects digest attributes from 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 deepHashCode(). See LogicalJoin as an example.

Specified by:

deepEquals in interface RelNode

Returns:

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

See Also:

deepHashCode()

deepHashCode

@API(since="1.25",
     status=MAINTAINED)
public int deepHashCode()

Compute hash code for RelNode digest.

Specified by:

deepHashCode in interface RelNode

See Also:

RelNode.deepEquals(Object)