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, org.apache.calcite.plan.RelOptNode, org.apache.calcite.rel.hint.Hintable, org.apache.calcite.rel.RelNode

Direct Known Subclasses:

LogicalSort

public abstract class Sort
extends org.apache.calcite.rel.SingleRel
implements org.apache.calcite.rel.hint.Hintable

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

Temporarily copy from calcite to cherry-pick [CALCITE-5107] and will be removed when upgrade the latest calcite.

Nested Class Summary

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

org.apache.calcite.rel.RelNode.Context

Field Summary

Fields

Modifier and Type	Field and Description
org.apache.calcite.rel.RelCollation	collation
@Nullable org.apache.calcite.rex.RexNode	fetch
protected com.google.common.collect.ImmutableList<org.apache.calcite.rel.hint.RelHint>	hints
@Nullable org.apache.calcite.rex.RexNode	offset

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 and Description
protected	Sort(org.apache.calcite.rel.RelInput input) Creates a Sort by parsing serialized output.
protected	Sort(org.apache.calcite.plan.RelOptCluster cluster, org.apache.calcite.plan.RelTraitSet traits, List<org.apache.calcite.rel.hint.RelHint> hints, org.apache.calcite.rel.RelNode child, org.apache.calcite.rel.RelCollation collation, @Nullable org.apache.calcite.rex.RexNode offset, @Nullable org.apache.calcite.rex.RexNode fetch) Creates a Sort.
protected	Sort(org.apache.calcite.plan.RelOptCluster cluster, org.apache.calcite.plan.RelTraitSet traits, org.apache.calcite.rel.RelNode child, org.apache.calcite.rel.RelCollation collation) Creates a Sort.
	Sort(org.apache.calcite.plan.RelOptCluster cluster, org.apache.calcite.plan.RelTraitSet traits, org.apache.calcite.rel.RelNode child, org.apache.calcite.rel.RelCollation collation, org.apache.calcite.rex.RexNode offset, org.apache.calcite.rex.RexNode fetch) Creates a Sort.

Method Summary

Modifier and Type	Method and Description
org.apache.calcite.rel.RelNode	accept(org.apache.calcite.rex.RexShuttle shuttle)
@Nullable org.apache.calcite.plan.RelOptCost	computeSelfCost(org.apache.calcite.plan.RelOptPlanner planner, org.apache.calcite.rel.metadata.RelMetadataQuery mq)
Sort	copy(org.apache.calcite.plan.RelTraitSet traitSet, List<org.apache.calcite.rel.RelNode> inputs)
Sort	copy(org.apache.calcite.plan.RelTraitSet traitSet, org.apache.calcite.rel.RelNode newInput, org.apache.calcite.rel.RelCollation newCollation)
abstract Sort	copy(org.apache.calcite.plan.RelTraitSet traitSet, org.apache.calcite.rel.RelNode newInput, org.apache.calcite.rel.RelCollation newCollation, @Nullable org.apache.calcite.rex.RexNode offset, @Nullable org.apache.calcite.rex.RexNode fetch)
org.apache.calcite.rel.RelWriter	explainTerms(org.apache.calcite.rel.RelWriter pw)
org.apache.calcite.rel.RelCollation	getCollation() Returns the array of RelFieldCollations asked for by the sort specification, from most significant to least significant.
com.google.common.collect.ImmutableList<org.apache.calcite.rel.hint.RelHint>	getHints()
List<org.apache.calcite.rex.RexNode>	getSortExps() Returns the sort expressions.
boolean	isEnforcer()

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, collectVariablesSet, collectVariablesUsed, deepEquals, deepHashCode, equals, explain, getCluster, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getRelDigest, getRelTypeName, getRowType, getTable, getTraitSet, getVariablesSet, hashCode, 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.hint.Hintable

attachHints, withHints

Methods inherited from interface org.apache.calcite.rel.RelNode

explain, fieldIsNullable

Field Detail

collation

public final org.apache.calcite.rel.RelCollation collation

offset

public final @Nullable org.apache.calcite.rex.RexNode offset

fetch

public final @Nullable org.apache.calcite.rex.RexNode fetch

hints

protected final com.google.common.collect.ImmutableList<org.apache.calcite.rel.hint.RelHint> hints

Constructor Detail

Sort

protected Sort(org.apache.calcite.plan.RelOptCluster cluster,
               org.apache.calcite.plan.RelTraitSet traits,
               org.apache.calcite.rel.RelNode child,
               org.apache.calcite.rel.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(org.apache.calcite.plan.RelOptCluster cluster,
            org.apache.calcite.plan.RelTraitSet traits,
            org.apache.calcite.rel.RelNode child,
            org.apache.calcite.rel.RelCollation collation,
            org.apache.calcite.rex.RexNode offset,
            org.apache.calcite.rex.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

protected Sort(org.apache.calcite.plan.RelOptCluster cluster,
               org.apache.calcite.plan.RelTraitSet traits,
               List<org.apache.calcite.rel.hint.RelHint> hints,
               org.apache.calcite.rel.RelNode child,
               org.apache.calcite.rel.RelCollation collation,
               @Nullable org.apache.calcite.rex.RexNode offset,
               @Nullable org.apache.calcite.rex.RexNode fetch)

Creates a Sort.

Parameters:

cluster - Cluster this relational expression belongs to

traits - Traits

hints - Hints for this node

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

protected Sort(org.apache.calcite.rel.RelInput input)

Creates a Sort by parsing serialized output.

Method Detail

copy

public final Sort copy(org.apache.calcite.plan.RelTraitSet traitSet,
                       List<org.apache.calcite.rel.RelNode> inputs)

Specified by:

copy in interface org.apache.calcite.rel.RelNode

Overrides:

copy in class org.apache.calcite.rel.AbstractRelNode

copy

public final Sort copy(org.apache.calcite.plan.RelTraitSet traitSet,
                       org.apache.calcite.rel.RelNode newInput,
                       org.apache.calcite.rel.RelCollation newCollation)

copy

public abstract Sort copy(org.apache.calcite.plan.RelTraitSet traitSet,
                          org.apache.calcite.rel.RelNode newInput,
                          org.apache.calcite.rel.RelCollation newCollation,
                          @Nullable org.apache.calcite.rex.RexNode offset,
                          @Nullable org.apache.calcite.rex.RexNode fetch)

computeSelfCost

public @Nullable org.apache.calcite.plan.RelOptCost computeSelfCost(org.apache.calcite.plan.RelOptPlanner planner,
                                                                    org.apache.calcite.rel.metadata.RelMetadataQuery mq)

The CPU cost of a Sort has three main cases:

• If fetch is zero, CPU cost is zero; otherwise,
• if the sort keys are empty, we don't need to sort, only step over the rows, and therefore the CPU cost is min(fetch + offset, inputRowCount) * bytesPerRow; otherwise
• we need to read and sort inputRowCount rows, with at most min(fetch + offset, inputRowCount) of them in the sort data structure at a time, giving a CPU cost of inputRowCount * log(min(fetch + offset, inputRowCount)) * bytesPerRow.

The cost model factors in row width via bytesPerRow, because sorts need to move rows around, not just compare them; by making the cost higher if rows are wider, we discourage pushing a Project through a Sort. We assume that each field is 4 bytes, and we add 3 'virtual fields' to represent the per-row overhead. Thus a 1-field row is (3 + 1) * 4 = 16 bytes; a 5-field row is (3 + 5) * 4 = 32 bytes.

The cost model does not consider a 5-field sort to be more expensive than, say, a 2-field sort, because both sorts will compare just one field most of the time.

Specified by:

computeSelfCost in interface org.apache.calcite.rel.RelNode

Overrides:

computeSelfCost in class org.apache.calcite.rel.AbstractRelNode

accept

public org.apache.calcite.rel.RelNode accept(org.apache.calcite.rex.RexShuttle shuttle)

Specified by:

accept in interface org.apache.calcite.rel.RelNode

Overrides:

accept in class org.apache.calcite.rel.AbstractRelNode

isEnforcer

public boolean isEnforcer()

Specified by:

isEnforcer in interface org.apache.calcite.rel.RelNode

Overrides:

isEnforcer in class org.apache.calcite.rel.AbstractRelNode

getCollation

public org.apache.calcite.rel.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] ].

getSortExps

public List<org.apache.calcite.rex.RexNode> getSortExps()

Returns the sort expressions.

explainTerms

public org.apache.calcite.rel.RelWriter explainTerms(org.apache.calcite.rel.RelWriter pw)

Overrides:

explainTerms in class org.apache.calcite.rel.SingleRel

getHints

public com.google.common.collect.ImmutableList<org.apache.calcite.rel.hint.RelHint> getHints()

Specified by:

getHints in interface org.apache.calcite.rel.hint.Hintable