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, OrderedRel, Prel

public class TopNPrel
extends SinglePrel
implements OrderedRel, Prel

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
protected org.apache.calcite.rel.RelCollation	collation
protected int	limit

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

input

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

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

Modifier and Type	Method and Description
boolean	canBeDropped() A method to return if this relational node can be dropped during optimization process.
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)
org.apache.calcite.rel.RelCollation	getCollation() A method to return ordering columns of the result.
BatchSchema.SelectionVectorMode	getEncoding() A Prel's own SelectionVector mode - i.e whether it generates an SV2, SV4 or None
org.apache.calcite.rex.RexNode	getFetch() Fetch value represented in RexNode.
int	getLimit()
org.apache.calcite.rex.RexNode	getOffset() Offset value represented in RexNode.
PhysicalOperator	getPhysicalOperator(PhysicalPlanCreator creator)
BatchSchema.SelectionVectorMode[]	getSupportedEncodings() Supported 'encodings' of a Prel indicates what are the acceptable modes of SelectionVector of its child Prel
Prel	prepareForLateralUnnestPipeline(List<org.apache.calcite.rel.RelNode> children) If the operator is in Lateral/Unnest pipeline, then it generates a new operator which knows how to process the rows accordingly during execution.

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, equals, explain, getChildExps, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getQuery, getRelTypeName, getRows, getRowType, getTable, getTraitSet, getVariablesSet, getVariablesStopped, hashCode, isDistinct, isKey, isValid, 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.drill.exec.planner.physical.Prel

accept, needsFinalColumnReordering

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, getVariablesSet, getVariablesStopped, isDistinct, isKey, isValid, isValid, metadata, onRegister, recomputeDigest, register, replaceInput

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

getCluster, getDescription, getDigest, getId, getTraitSet

Methods inherited from interface java.lang.Iterable

forEach, iterator, spliterator

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

Specified by:

getPhysicalOperator in interface Prel

Throws:

IOException

getCollation

public org.apache.calcite.rel.RelCollation getCollation()

Description copied from interface: OrderedRel

A method to return ordering columns of the result.

Specified by:

getCollation in interface OrderedRel

Returns:

Collation order of the output.

getOffset

public org.apache.calcite.rex.RexNode getOffset()

Description copied from interface: OrderedRel

Offset value represented in RexNode.

Specified by:

getOffset in interface OrderedRel

Returns:

offset.

getFetch

public org.apache.calcite.rex.RexNode getFetch()

Description copied from interface: OrderedRel

Fetch value represented in RexNode.

Specified by:

getFetch in interface OrderedRel

Returns:

fetch

canBeDropped

public boolean canBeDropped()

Description copied from interface: OrderedRel

A method to return if this relational node can be dropped during optimization process.

Specified by:

canBeDropped in interface OrderedRel

Returns:

true if this node can be dropped, false otherwise.

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

getLimit

public int getLimit()

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

Specified by:

getEncoding in interface Prel

prepareForLateralUnnestPipeline

public Prel prepareForLateralUnnestPipeline(List<org.apache.calcite.rel.RelNode> children)

Description copied from interface: Prel

If the operator is in Lateral/Unnest pipeline, then it generates a new operator which knows how to process the rows accordingly during execution. eg: TopNPrel -> SortPrel and LimitPrel Other operators like FilterPrel, ProjectPrel etc will add an implicit row id to the output.

Specified by:

prepareForLateralUnnestPipeline in interface Prel