Class QueryJoinOptimizer.JoinVisitor

java.lang.Object

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

org.eclipse.rdf4j.query.algebra.evaluation.optimizer.QueryJoinOptimizer.JoinVisitor

All Implemented Interfaces:

QueryModelVisitor<RuntimeException>

Enclosing class:

QueryJoinOptimizer

private static class QueryJoinOptimizer.JoinVisitor
extends AbstractSimpleQueryModelVisitor<RuntimeException>

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	QueryJoinOptimizer.JoinVisitor.StatementPatternVarCollector

Field Summary

Fields

Modifier and Type	Field	Description
(package private) Set<String>	boundVars
private final EvaluationStatistics	statistics

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	JoinVisitor(EvaluationStatistics statistics, boolean trackResultSize)

Method Summary

Modifier and Type	Method	Description
private int	countConstantVars(List<Var> vars)
protected <M extends Map<Var,Integer>> void	fillVarFreqMap(List<Var> varList, M varFreqMap)
protected List<Extension>	getExtensions(List<TupleExpr> expressions)
private List<TupleExpr>	getExtensionTupleExprs(List<TupleExpr> expressions)
protected int	getForeignVarFreq(List<Var> ownUnboundVars, Map<Var,Integer> varFreqMap)
protected <L extends List<TupleExpr>> L	getJoinArgs(TupleExpr tupleExpr, L joinArgs)
private TupleExpr	getNextSubselect(List<TupleExpr> currentList, List<TupleExpr> joinArgs)
protected List<Var>	getStatementPatternVars(TupleExpr tupleExpr)
protected List<TupleExpr>	getSubSelects(List<TupleExpr> expressions)
protected double	getTupleExprCost(TupleExpr tupleExpr, Map<TupleExpr, Double> cardinalityMap, Map<TupleExpr, List<Var>> varsMap, Map<Var,Integer> varFreqMap)
protected List<Var>	getUnboundVars(Iterable<Var> vars)	Deprecated, for removal: This API element is subject to removal in a future version.
protected List<Var>	getUnboundVars(List<Var> vars)
void	meet(Join node)
void	meet(LeftJoin leftJoin)
void	meet(StatementPattern node)
private void	optimizePriorityJoin(Set<String> origBoundVars, TupleExpr join)
protected List<TupleExpr>	reorderSubselects(List<TupleExpr> subSelects)	Determines an optimal ordering of subselect join arguments, based on variable bindings.
protected TupleExpr	selectNextTupleExpr(List<TupleExpr> expressions, Map<TupleExpr, Double> cardinalityMap, Map<TupleExpr, List<Var>> varsMap, Map<Var,Integer> varFreqMap)	Selects from a list of tuple expressions the next tuple expression that should be evaluated.

Methods inherited from class 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, meetBinaryTupleOperator, meetBinaryValueOperator, meetCompareSubQueryValueOperator, meetNAryValueOperator, meetOther, meetSubQueryValueOperator, meetUnaryTupleOperator, meetUnaryValueOperator, meetUnsupported, meetUpdateExpr

Methods inherited from class Object

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

Field Details

statistics

private final EvaluationStatistics statistics

boundVars

Set<String> boundVars

Constructor Details

JoinVisitor

protected JoinVisitor(EvaluationStatistics statistics,
 boolean trackResultSize)

Method Details

meet

public void meet(LeftJoin leftJoin)

Specified by:

meet in interface QueryModelVisitor<RuntimeException>

Overrides:

meet in class AbstractSimpleQueryModelVisitor<RuntimeException>

meet

public void meet(StatementPattern node)
          throws RuntimeException

Specified by:

meet in interface QueryModelVisitor<RuntimeException>

Overrides:

meet in class AbstractSimpleQueryModelVisitor<RuntimeException>

Throws:

RuntimeException

optimizePriorityJoin

private void optimizePriorityJoin(Set<String> origBoundVars,
 TupleExpr join)

meet

public void meet(Join node)

Specified by:

meet in interface QueryModelVisitor<RuntimeException>

Overrides:

meet in class AbstractSimpleQueryModelVisitor<RuntimeException>

getJoinArgs

protected <L extends List<TupleExpr>> L getJoinArgs(TupleExpr tupleExpr,
 L joinArgs)

getStatementPatternVars

protected List<Var> getStatementPatternVars(TupleExpr tupleExpr)

fillVarFreqMap

protected <M extends Map<Var,Integer>> void fillVarFreqMap(List<Var> varList,
 M varFreqMap)

getExtensions

protected List<Extension> getExtensions(List<TupleExpr> expressions)

getExtensionTupleExprs

private List<TupleExpr> getExtensionTupleExprs(List<TupleExpr> expressions)

getSubSelects

protected List<TupleExpr> getSubSelects(List<TupleExpr> expressions)

reorderSubselects

protected List<TupleExpr> reorderSubselects(List<TupleExpr> subSelects)

Determines an optimal ordering of subselect join arguments, based on variable bindings. An ordering is considered optimal if for each consecutive element it holds that first of all its shared variables with all previous elements is maximized, and second, the union of all its variables with all previous elements is maximized.

Example: reordering

  [f] [a b c] [e f] [a d] [b e]

should result in:

  [a b c] [a d] [b e] [e f] [f]

Parameters:

subSelects - the original ordering of expressions

Returns:

the optimized ordering of expressions

getNextSubselect

private TupleExpr getNextSubselect(List<TupleExpr> currentList,
 List<TupleExpr> joinArgs)

selectNextTupleExpr

protected TupleExpr selectNextTupleExpr(List<TupleExpr> expressions,
 Map<TupleExpr, Double> cardinalityMap,
 Map<TupleExpr, List<Var>> varsMap,
 Map<Var,Integer> varFreqMap)

Selects from a list of tuple expressions the next tuple expression that should be evaluated. This method selects the tuple expression with highest number of bound variables, preferring variables that have been bound in other tuple expressions over variables with a fixed value.

getTupleExprCost

protected double getTupleExprCost(TupleExpr tupleExpr,
 Map<TupleExpr, Double> cardinalityMap,
 Map<TupleExpr, List<Var>> varsMap,
 Map<Var,Integer> varFreqMap)

countConstantVars

private int countConstantVars(List<Var> vars)

getUnboundVars

@Deprecated(forRemoval=true,
            since="4.1.0")
protected List<Var> getUnboundVars(Iterable<Var> vars)

Deprecated, for removal: This API element is subject to removal in a future version.

getUnboundVars

protected List<Var> getUnboundVars(List<Var> vars)

getForeignVarFreq

protected int getForeignVarFreq(List<Var> ownUnboundVars,
 Map<Var,Integer> varFreqMap)