Class SimpleJoinOrderingQueryOptimizer

java.lang.Object

se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.PhysicalOptimizerBase

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

All Implemented Interfaces:

PhysicalOptimizer

public class SimpleJoinOrderingQueryOptimizer
extends PhysicalOptimizerBase

This class implements a simple query optimizer that focuses only on join ordering, for which it uses an enumeration algorithm to optimize any subplan that consists of a group of joins. The concrete enumeration algorithm to be used for this purpose is not hard-coded but, instead, can be specified by means of providing an implementation of JoinPlanOptimizer.

Field Summary

Fields

Modifier and Type	Field	Description
protected final JoinPlanOptimizer	joinPlanOptimizer

Constructor Summary

Constructors

Constructor	Description
SimpleJoinOrderingQueryOptimizer(JoinPlanOptimizer joinPlanOptimizer)

Method Summary

Modifier and Type	Method	Description
boolean	assumesLogicalMultiwayJoins()
protected PhysicalPlan[]	getOptimizedSubPlans(PhysicalPlan plan, QueryProcContext ctxt)
protected boolean	hasMultiwayJoinAsRoot(PhysicalPlan plan)
boolean	keepMultiwayJoinsInInitialPhysicalPlan()	Return true if this optimizer expects that multiway joins are carried over from the given logical plan into the initial physical plan.
Pair<PhysicalPlan,PhysicalOptimizationStats>	optimize(PhysicalPlan initialPlan, QueryProcContext ctxt)
PhysicalPlan	optimizePlan(PhysicalPlan plan, QueryProcContext ctxt)

Methods inherited from class se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.PhysicalOptimizerBase

optimize

Methods inherited from class java.lang.Object

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

Field Details

joinPlanOptimizer

protected final JoinPlanOptimizer joinPlanOptimizer

Constructor Details

SimpleJoinOrderingQueryOptimizer

public SimpleJoinOrderingQueryOptimizer(JoinPlanOptimizer joinPlanOptimizer)

Method Details

assumesLogicalMultiwayJoins

public boolean assumesLogicalMultiwayJoins()

keepMultiwayJoinsInInitialPhysicalPlan

public boolean keepMultiwayJoinsInInitialPhysicalPlan()

Description copied from class: PhysicalOptimizerBase

Return true if this optimizer expects that multiway joins are carried over from the given logical plan into the initial physical plan. The

invalid reference

#optimize(LogicalPlan)

function passes this flag as the second argument of the

invalid reference

LogicalToPhysicalPlanConverter#convert(LogicalPlan, boolean)

function.

Specified by:

keepMultiwayJoinsInInitialPhysicalPlan in class PhysicalOptimizerBase

optimize

public Pair<PhysicalPlan,PhysicalOptimizationStats> optimize(PhysicalPlan initialPlan,
 QueryProcContext ctxt)
                                                      throws PhysicalOptimizationException

Specified by:

optimize in class PhysicalOptimizerBase

Throws:

PhysicalOptimizationException

optimizePlan

public PhysicalPlan optimizePlan(PhysicalPlan plan,
 QueryProcContext ctxt)
                          throws PhysicalOptimizationException

Throws:

PhysicalOptimizationException

getOptimizedSubPlans

protected PhysicalPlan[] getOptimizedSubPlans(PhysicalPlan plan,
 QueryProcContext ctxt)
                                       throws PhysicalOptimizationException

Throws:

PhysicalOptimizationException

hasMultiwayJoinAsRoot

protected boolean hasMultiwayJoinAsRoot(PhysicalPlan plan)