Package se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.simple

Class CostModelBasedGreedyJoinPlanOptimizerImpl.GreedyEnumerationAlgorithm

java.lang.Object

se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.simple.CostModelBasedGreedyJoinPlanOptimizerImpl.GreedyEnumerationAlgorithm

All Implemented Interfaces:

JoinPlanOptimizerBase.EnumerationAlgorithm

Enclosing class:

CostModelBasedGreedyJoinPlanOptimizerImpl

protected class CostModelBasedGreedyJoinPlanOptimizerImpl.GreedyEnumerationAlgorithm
extends Object
implements JoinPlanOptimizerBase.EnumerationAlgorithm

Field Summary

Fields

Modifier and Type	Field	Description
protected final List<PhysicalPlan>	subplans

Constructor Summary

Constructors

Constructor	Description
GreedyEnumerationAlgorithm(List<PhysicalPlan> subplans)

Method Summary

Modifier and Type	Method	Description
protected PhysicalPlan	addNextBestJoin(PhysicalPlan currentPlan)	Creates a binary join plan with the given plan as left child and one of the remaining subplans (see subplans) as the right child.
protected PhysicalPlan	chooseFirstSubplan()	Compares all available subplans (see subplans) in terms of their respective costs (as estimated by using the CostModelBasedGreedyJoinPlanOptimizerImpl.costModel) and returns the one with the lowest estimated cost.
protected Map<Integer,List<PhysicalPlan>>	createNextPossiblePlans(PhysicalPlan currentPlan)	Creates all possible binary join plans with the given plan as left child and one of the remaining subplans (see subplans) as the right child, as well as plans with unary (gpAdd-based) joins with the given plan as the child.
PhysicalPlan	getResultingPlan()

Methods inherited from class java.lang.Object

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

Field Details

subplans

protected final List<PhysicalPlan> subplans

Constructor Details

GreedyEnumerationAlgorithm

public GreedyEnumerationAlgorithm(List<PhysicalPlan> subplans)

Method Details

getResultingPlan

public PhysicalPlan getResultingPlan()
                              throws PhysicalOptimizationException

Specified by:

getResultingPlan in interface JoinPlanOptimizerBase.EnumerationAlgorithm

Throws:

PhysicalOptimizationException

chooseFirstSubplan

protected PhysicalPlan chooseFirstSubplan()
                                   throws PhysicalOptimizationException

Compares all available subplans (see subplans) in terms of their respective costs (as estimated by using the CostModelBasedGreedyJoinPlanOptimizerImpl.costModel) and returns the one with the lowest estimated cost.

Throws:

PhysicalOptimizationException

addNextBestJoin

protected PhysicalPlan addNextBestJoin(PhysicalPlan currentPlan)
                                throws PhysicalOptimizationException

Creates a binary join plan with the given plan as left child and one of the remaining subplans (see subplans) as the right child. The subplan that is picked to be the right child is the one for which the returned plan has the minimum cost among all plans that can be constructed in this way.

Throws:

PhysicalOptimizationException

createNextPossiblePlans

protected Map<Integer,List<PhysicalPlan>> createNextPossiblePlans(PhysicalPlan currentPlan)

Creates all possible binary join plans with the given plan as left child and one of the remaining subplans (see subplans) as the right child, as well as plans with unary (gpAdd-based) joins with the given plan as the child. In the returned map, the index that each of these remaining subplans has within subplans is mapped to the collection of possible join plans created using this subplan.