com.bigdata.rdf.sparql.ast.optimizers

Class ASTCardinalityOptimizer

java.lang.Object

com.bigdata.rdf.sparql.ast.optimizers.AbstractJoinGroupOptimizer

com.bigdata.rdf.sparql.ast.optimizers.ASTCardinalityOptimizer

All Implemented Interfaces:

IASTOptimizer

public class ASTCardinalityOptimizer
extends AbstractJoinGroupOptimizer
implements IASTOptimizer

Calculate the estimated cardinality of a join group. TODO Calculate estimated cardinality of other things like subqueries and unions.

Author:

mikepersonick

Constructor Summary

Constructors

Constructor and Description
ASTCardinalityOptimizer()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	optimizeJoinGroup(AST2BOpContext ctx, StaticAnalysis sa, IBindingSet[] bSets, JoinGroupNode group) Calculate the estimated cardinality of a join group.

Methods inherited from class com.bigdata.rdf.sparql.ast.optimizers.AbstractJoinGroupOptimizer

optimize

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.bigdata.rdf.sparql.ast.optimizers.IASTOptimizer

optimize

Constructor Detail

ASTCardinalityOptimizer

public ASTCardinalityOptimizer()

Method Detail

optimizeJoinGroup

protected void optimizeJoinGroup(AST2BOpContext ctx,
                     StaticAnalysis sa,
                     IBindingSet[] bSets,
                     JoinGroupNode group)

Calculate the estimated cardinality of a join group. We will do this by first dividing the group into subgroups that share variables. For each subgroup, we will calculate the estimated cardinality of that subgroup. Then we will multiple those cardinalities together to get an estimate of cardinality for the whole group. The estimated cardinality of a subgroup will be calculated using the same logic contained in the ASTStaticJoinOptimizer.

Specified by:

optimizeJoinGroup in class AbstractJoinGroupOptimizer