org.apache.calcite.rel.core

Class Sort

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.SingleRel

org.apache.calcite.rel.core.Sort

All Implemented Interfaces:

Cloneable, RelOptNode, RelNode

Direct Known Subclasses:

Bindables.BindableSort, EnumerableSort, JdbcRules.JdbcSort, LogicalSort

public abstract class Sort
extends SingleRel

Relational expression that imposes a particular sort order on its input without otherwise changing its content.

Field Summary

Fields

Modifier and Type	Field and Description
RelCollation	collation
RexNode	fetch
protected com.google.common.collect.ImmutableList<RexNode>	fieldExps
RexNode	offset

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

digest, id, rowType, traitSet

Constructor Summary

Constructors

Constructor and Description
Sort(RelInput input) Creates a Sort by parsing serialized output.
Sort(RelOptCluster cluster, RelTraitSet traits, RelNode child, RelCollation collation) Creates a Sort.
Sort(RelOptCluster cluster, RelTraitSet traits, RelNode child, RelCollation collation, RexNode offset, RexNode fetch) Creates a Sort.

Method Summary

Methods

Modifier and Type	Method and Description
RelNode	accept(RexShuttle shuttle) Accepts a visit from a shuttle.
RelOptCost	computeSelfCost(RelOptPlanner planner) Returns the cost of this plan (not including children).
Sort	copy(RelTraitSet traitSet, List<RelNode> inputs) Creates a copy of this relational expression, perhaps changing traits and inputs.
Sort	copy(RelTraitSet traitSet, RelNode newInput, RelCollation newCollation)
abstract Sort	copy(RelTraitSet traitSet, RelNode newInput, RelCollation newCollation, RexNode offset, RexNode fetch)
RelWriter	explainTerms(RelWriter pw) Describes the inputs and attributes of this relational expression.
List<RexNode>	getChildExps() Returns a list of this relational expression's child expressions.
RelCollation	getCollation() Returns the array of RelFieldCollations asked for by the sort specification, from most significant to least significant.
List<RelCollation>	getCollationList() Returns a description of the physical ordering (or orderings) of this relational expression.

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, collectVariablesSet, collectVariablesUsed, computeDigest, explain, getCluster, 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

public final RelCollation collation

fieldExps

protected final com.google.common.collect.ImmutableList<RexNode> fieldExps

offset

public final RexNode offset

fetch

public final RexNode fetch

Constructor Detail

Sort

public Sort(RelOptCluster cluster,
    RelTraitSet traits,
    RelNode child,
    RelCollation collation)

Creates a Sort.

Parameters:

cluster - Cluster this relational expression belongs to

traits - Traits

child - input relational expression

collation - array of sort specifications

Sort

public Sort(RelOptCluster cluster,
    RelTraitSet traits,
    RelNode child,
    RelCollation collation,
    RexNode offset,
    RexNode fetch)

Creates a Sort.

Parameters:

cluster - Cluster this relational expression belongs to

traits - Traits

child - input relational expression

collation - array of sort specifications

offset - Expression for number of rows to discard before returning first row

fetch - Expression for number of rows to fetch

Sort

public Sort(RelInput input)

Creates a Sort by parsing serialized output.

Method Detail

copy

public final Sort 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

public final Sort copy(RelTraitSet traitSet,
        RelNode newInput,
        RelCollation newCollation)

copy

public abstract Sort copy(RelTraitSet traitSet,
        RelNode newInput,
        RelCollation newCollation,
        RexNode offset,
        RexNode fetch)

computeSelfCost

public RelOptCost computeSelfCost(RelOptPlanner planner)

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

Returns:

Cost of this plan (not including children)

getChildExps

public List<RexNode> getChildExps()

Description copied from interface: RelNode

Returns a list of this relational expression's child expressions. (These are scalar expressions, and so do not include the relational inputs that are returned by RelNode.getInputs().

The caller should treat the list as unmodifiable; typical implementations will return an immutable list. If there are no child expressions, returns an empty list, not null.

Specified by:

getChildExps in interface RelNode

Overrides:

getChildExps in class AbstractRelNode

Returns:

List of this relational expression's child expressions

See Also:

RelNode.accept(org.apache.calcite.rex.RexShuttle)

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.

Specified by:

accept in interface RelNode

Overrides:

accept in class AbstractRelNode

Parameters:

shuttle - Shuttle

Returns:

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

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] ].

getCollationList

public List<RelCollation> getCollationList()

Description copied from interface: RelNode

Returns a description of the physical ordering (or orderings) of this relational expression. Never null.

Specified by:

getCollationList in interface RelNode

Overrides:

getCollationList in class AbstractRelNode

Returns:

Description of the physical ordering (or orderings) of this relational expression. Never null

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 SingleRel

Parameters:

pw - Plan writer

Returns:

Plan writer for fluent-explain pattern