Package org.apache.calcite.rel.core

Class Spool

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.SingleRel

org.apache.calcite.rel.core.Spool

All Implemented Interfaces:

Cloneable, RelOptNode, RelNode

Direct Known Subclasses:

TableSpool

public abstract class Spool
extends SingleRel

Relational expression that iterates over its input and, in addition to returning its results, will forward them into other consumers.

NOTE: The current API is experimental and subject to change without notice.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	Spool.Type	Enumeration representing spool read / write type.

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

RelNode.Context

Field Summary

Fields

Modifier and Type	Field	Description
final Spool.Type	readType	How the spool consumes elements from its input.
final Spool.Type	writeType	How the spool forwards elements to consumers.

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	Spool(RelOptCluster cluster, RelTraitSet traitSet, RelNode input, Spool.Type readType, Spool.Type writeType)	Creates a Spool.

Method Summary

Modifier and Type	Method	Description
final RelNode	copy(RelTraitSet traitSet, List<RelNode> inputs)	Creates a copy of this relational expression, perhaps changing traits and inputs.
protected abstract Spool	copy(RelTraitSet traitSet, RelNode input, Spool.Type readType, Spool.Type writeType)
RelWriter	explainTerms(RelWriter pw)	Describes the inputs and attributes of this relational expression.

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, computeSelfCost, 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

readType

public final Spool.Type readType

How the spool consumes elements from its input.

• EAGER: the spool consumes the elements from its input at once at the initial request;
• LAZY: the spool consumes the elements from its input one by one by request.

writeType

public final Spool.Type writeType

How the spool forwards elements to consumers.

• EAGER: the spool forwards each element as soon as it returns it;
• LAZY: the spool forwards all elements at once when it is done returning all of them.

Constructor Details

Spool

protected Spool(RelOptCluster cluster,
 RelTraitSet traitSet,
 RelNode input,
 Spool.Type readType,
 Spool.Type writeType)

Creates a Spool.

Method Details

copy

public final 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

copy

protected abstract Spool copy(RelTraitSet traitSet,
 RelNode input,
 Spool.Type readType,
 Spool.Type writeType)

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