com.bigdata.rdf.sparql.ast.optimizers

Class ASTHashJoinOptimizer

java.lang.Object

com.bigdata.rdf.sparql.ast.optimizers.ASTHashJoinOptimizer

All Implemented Interfaces:

IASTOptimizer

public class ASTHashJoinOptimizer
extends Object
implements IASTOptimizer

Rewrites join groups having one or more joins which would involve a full cross product as hash joins of sub-groups where there is a constraint imposed indirectly via a FILTER operating across the variables bound by the joins. This handles queries such as BSBM Q5.

Version:

$Id$

Author:

Bryan Thompson

See Also:

https://sourceforge.net/apps/trac/bigdata/ticket/253

Constructor Summary

Constructors

Constructor and Description
ASTHashJoinOptimizer()

Method Summary

Methods

Modifier and Type	Method and Description
QueryNodeWithBindingSet	optimize(AST2BOpContext context, QueryNodeWithBindingSet input) Optimize the AST.

Methods inherited from class java.lang.Object

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

Constructor Detail

ASTHashJoinOptimizer

public ASTHashJoinOptimizer()

Method Detail

optimize

public QueryNodeWithBindingSet optimize(AST2BOpContext context,
                               QueryNodeWithBindingSet input)

Description copied from interface: IASTOptimizer

Optimize the AST.

Specified by:

optimize in interface IASTOptimizer

Parameters:

context - The evaluation context.

input - The input to the optimizer, consisting of a queryNode and input binding set.

Returns:

An instance of type QueryNodeWithBindingSet.