org.apache.drill.exec.planner.physical

Class TopNPrel

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.SingleRel

org.apache.drill.exec.planner.physical.SinglePrel

org.apache.drill.exec.planner.physical.TopNPrel

All Implemented Interfaces:

Cloneable, Iterable<Prel>, org.apache.calcite.plan.RelOptNode, org.apache.calcite.rel.RelNode, DrillRelNode, Prel

public class TopNPrel
extends SinglePrel

Field Summary

Fields

Modifier and Type	Field and Description
protected org.apache.calcite.rel.RelCollation	collation
protected int	limit

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

digest, id, rowType, traitSet

Fields inherited from interface org.apache.drill.exec.planner.physical.Prel

DRILL_PHYSICAL, logger

Constructor Summary

Constructors

Constructor and Description
TopNPrel(org.apache.calcite.plan.RelOptCluster cluster, org.apache.calcite.plan.RelTraitSet traitSet, org.apache.calcite.rel.RelNode child, int limit, org.apache.calcite.rel.RelCollation collation)

Method Summary

Methods

Modifier and Type	Method and Description
org.apache.calcite.plan.RelOptCost	computeSelfCost(org.apache.calcite.plan.RelOptPlanner planner, org.apache.calcite.rel.metadata.RelMetadataQuery mq) Cost of doing Top-N is proportional to M log N where M is the total number of input rows and N is the limit for Top-N.
org.apache.calcite.rel.RelNode	copy(org.apache.calcite.plan.RelTraitSet traitSet, List<org.apache.calcite.rel.RelNode> inputs)
org.apache.calcite.rel.RelWriter	explainTerms(org.apache.calcite.rel.RelWriter pw)
BatchSchema.SelectionVectorMode	getEncoding() A Prel's own SelectionVector mode - i.e whether it generates an SV2, SV4 or None
PhysicalOperator	getPhysicalOperator(PhysicalPlanCreator creator)
BatchSchema.SelectionVectorMode[]	getSupportedEncodings() Supported 'encodings' of a Prel indicates what are the acceptable modes of SelectionVector of its child Prel

Methods inherited from class org.apache.drill.exec.planner.physical.SinglePrel

accept, iterator, needsFinalColumnReordering

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, computeDigest, computeSelfCost, explain, getChildExps, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getQuery, getRelTypeName, getRows, getRowType, getTable, getTraitSet, getVariablesSet, getVariablesStopped, isDistinct, isKey, isValid, isValid, metadata, onRegister, recomputeDigest, register, sole, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

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

accept, accept, childrenAccept, collectVariablesSet, collectVariablesUsed, computeSelfCost, estimateRowCount, explain, getChildExps, getCollationList, getConvention, getCorrelVariable, getExpectedInputRowType, getInput, getInputs, getQuery, getRelTypeName, getRows, getRowType, getTable, getVariablesStopped, isDistinct, isKey, isValid, metadata, onRegister, recomputeDigest, register, replaceInput

Methods inherited from interface org.apache.calcite.plan.RelOptNode

getCluster, getDescription, getDigest, getId, getTraitSet

Field Detail

limit

protected int limit

collation

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

Constructor Detail

TopNPrel

public TopNPrel(org.apache.calcite.plan.RelOptCluster cluster,
        org.apache.calcite.plan.RelTraitSet traitSet,
        org.apache.calcite.rel.RelNode child,
        int limit,
        org.apache.calcite.rel.RelCollation collation)

Method Detail

copy

public org.apache.calcite.rel.RelNode 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

getPhysicalOperator

public PhysicalOperator getPhysicalOperator(PhysicalPlanCreator creator)
                                     throws IOException

Throws:

IOException

computeSelfCost

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

Cost of doing Top-N is proportional to M log N where M is the total number of input rows and N is the limit for Top-N. This makes Top-N preferable to Sort since cost of full Sort is proportional to M log M .

Specified by:

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

Overrides:

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

explainTerms

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

Overrides:

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

getSupportedEncodings

public BatchSchema.SelectionVectorMode[] getSupportedEncodings()

Description copied from interface: Prel

Supported 'encodings' of a Prel indicates what are the acceptable modes of SelectionVector of its child Prel

Specified by:

getSupportedEncodings in interface Prel

Overrides:

getSupportedEncodings in class SinglePrel

getEncoding

public BatchSchema.SelectionVectorMode getEncoding()

Description copied from interface: Prel

A Prel's own SelectionVector mode - i.e whether it generates an SV2, SV4 or None