Package se.liu.ida.hefquin.engine.queryproc.impl.loptimizer.heuristics.utils

Class JoinAnalyzer

java.lang.Object

se.liu.ida.hefquin.engine.queryproc.impl.loptimizer.heuristics.utils.JoinAnalyzer

public class JoinAnalyzer
extends Object

Constructor Summary

Constructors

Constructor	Description
JoinAnalyzer()

Method Summary

Modifier and Type	Method	Description
static int	countDuplicates(List<org.apache.jena.graph.Node> vars)	Sum the number of duplicates for each variable e.g., if the input contains three ?
static int	countNumOfChainJoins(QueryAnalyzer plan)
static int	countNumOfChainJoins(QueryAnalyzer plan_l, QueryAnalyzer plan_r)
static int	countNumOfJoinPairs(List<org.apache.jena.graph.Node> vars_a, List<org.apache.jena.graph.Node> vars_b)	For each occurrence of a variable in the second list, check whether there exists a matching partner (the same variable) in the first list.
static int	countNumOfJoinsWithSameObj(QueryAnalyzer plan)
static int	countNumOfJoinsWithSameObj(QueryAnalyzer plan_l, QueryAnalyzer plan_r)
static int	countNumOfJoinsWithSameSub(QueryAnalyzer plan)	Count number of different types of joins for a given plan; - s-s joins: subject-subject - o-o joins: object-object joins - chain joins: object-subject and subject-object joins - unusual joins: subject-predicate, predicate-object, predicate-predicate joins
static int	countNumOfJoinsWithSameSub(QueryAnalyzer plan_l, QueryAnalyzer plan_r)	Count number of different types of joins between two given sub-plans
static int	countNumOfUnusualJoins(QueryAnalyzer plan)
static int	countNumOfUnusualJoins(QueryAnalyzer plan_l, QueryAnalyzer plan_r)

Methods inherited from class java.lang.Object

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

Constructor Details

JoinAnalyzer

public JoinAnalyzer()

Method Details

countNumOfJoinsWithSameSub

public static int countNumOfJoinsWithSameSub(QueryAnalyzer plan)

Count number of different types of joins for a given plan; - s-s joins: subject-subject - o-o joins: object-object joins - chain joins: object-subject and subject-object joins - unusual joins: subject-predicate, predicate-object, predicate-predicate joins

countNumOfJoinsWithSameObj

public static int countNumOfJoinsWithSameObj(QueryAnalyzer plan)

countNumOfChainJoins

public static int countNumOfChainJoins(QueryAnalyzer plan)

countNumOfUnusualJoins

public static int countNumOfUnusualJoins(QueryAnalyzer plan)

countNumOfJoinsWithSameSub

public static int countNumOfJoinsWithSameSub(QueryAnalyzer plan_l,
 QueryAnalyzer plan_r)

Count number of different types of joins between two given sub-plans

countNumOfJoinsWithSameObj

public static int countNumOfJoinsWithSameObj(QueryAnalyzer plan_l,
 QueryAnalyzer plan_r)

countNumOfChainJoins

public static int countNumOfChainJoins(QueryAnalyzer plan_l,
 QueryAnalyzer plan_r)

countNumOfUnusualJoins

public static int countNumOfUnusualJoins(QueryAnalyzer plan_l,
 QueryAnalyzer plan_r)

countDuplicates

public static int countDuplicates(List<org.apache.jena.graph.Node> vars)

Sum the number of duplicates for each variable e.g., if the input contains three ?s variable, the number of duplicates is 2

countNumOfJoinPairs

public static int countNumOfJoinPairs(List<org.apache.jena.graph.Node> vars_a,
 List<org.apache.jena.graph.Node> vars_b)

For each occurrence of a variable in the second list, check whether there exists a matching partner (the same variable) in the first list. If exists, increase the "numOfJoinPairs" by 1, and remove the matched variable (instance) from the first list. Otherwise, move to the next variable. Repeat this process until all occurrences of variables in the second list have been checked. Note: If a variable occurs multiple times, each occurrence is counted in join pairs only once.