Package org.eclipse.rdf4j.federated.optimizer

Class StatementGroupAndJoinOptimizer

java.lang.Object

org.eclipse.rdf4j.query.algebra.helpers.AbstractSimpleQueryModelVisitor<OptimizationException>

org.eclipse.rdf4j.federated.optimizer.StatementGroupAndJoinOptimizer

All Implemented Interfaces:

FedXOptimizer, QueryModelVisitor<OptimizationException>

public class StatementGroupAndJoinOptimizer
extends AbstractSimpleQueryModelVisitor<OptimizationException>
implements FedXOptimizer

Optimizer with the following tasks: 1. Group ExclusiveStatement into ExclusiveGroup 2. Adjust the join order using DefaultFedXCostModel

Author:

as

Field Summary

Fields

Modifier and Type	Field	Description
protected QueryInfo	queryInfo

Constructor Summary

Constructors

Constructor	Description
StatementGroupAndJoinOptimizer(QueryInfo queryInfo, FedXCostModel costModel)

Method Summary

Modifier and Type	Method	Description
protected double	estimateCost(TupleExpr tupleExpr, Set<String> joinVars)
protected List<TupleExpr>	formGroups(List<TupleExpr> originalArgs)	Group ExclusiveStatements having the same source into an ExclusiveGroup.
void	meet(Service tupleExpr)
protected void	meetNJoin(NJoin node)
void	meetOther(QueryModelNode node)
void	optimize(TupleExpr tupleExpr)	Optimize the provided tuple expression
protected List<TupleExpr>	optimizeJoinOrder(List<TupleExpr> joinArgs)	Join Order Optimizer Group -> Statements according to number of free Variables Additional Heuristics: - ExclusiveGroups are cheaper than any other subquery - owned statements are cheaper if they have a single free variable

Methods inherited from class org.eclipse.rdf4j.query.algebra.helpers.AbstractSimpleQueryModelVisitor

meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meetBinaryTupleOperator, meetBinaryValueOperator, meetCompareSubQueryValueOperator, meetNAryValueOperator, meetSubQueryValueOperator, meetUnaryTupleOperator, meetUnaryValueOperator, meetUnsupported, meetUpdateExpr

Methods inherited from class java.lang.Object

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

Field Detail

queryInfo

protected final QueryInfo queryInfo

Constructor Detail

StatementGroupAndJoinOptimizer

public StatementGroupAndJoinOptimizer(QueryInfo queryInfo,
                                      FedXCostModel costModel)

Method Detail

optimize

public void optimize(TupleExpr tupleExpr)

Description copied from interface: FedXOptimizer

Optimize the provided tuple expression

Specified by:

optimize in interface FedXOptimizer

meet

public void meet(Service tupleExpr)

Specified by:

meet in interface QueryModelVisitor<OptimizationException>

Overrides:

meet in class AbstractSimpleQueryModelVisitor<OptimizationException>

meetOther

public void meetOther(QueryModelNode node)

Specified by:

meetOther in interface QueryModelVisitor<OptimizationException>

Overrides:

meetOther in class AbstractSimpleQueryModelVisitor<OptimizationException>

meetNJoin

protected void meetNJoin(NJoin node)

formGroups

protected List<TupleExpr> formGroups(List<TupleExpr> originalArgs)

Group ExclusiveStatements having the same source into an ExclusiveGroup.

Parameters:

originalArgs -

Returns:

the new (potentially grouped) join arguments. If empty, the join will not produce any results.

optimizeJoinOrder

protected List<TupleExpr> optimizeJoinOrder(List<TupleExpr> joinArgs)

Join Order Optimizer Group -> Statements according to number of free Variables Additional Heuristics: - ExclusiveGroups are cheaper than any other subquery - owned statements are cheaper if they have a single free variable

Parameters:

joinArgs -

Returns:

estimateCost

protected double estimateCost(TupleExpr tupleExpr,
                              Set<String> joinVars)