/* // $Id: //guest/julian_hyde/saffron/src/main/saffron/rel/plan/PlanNestedLoopJoin.java#1 $ // Saffron preprocessor and data engine // Copyright (C) 2002 Julian Hyde <julian.hyde@mail.com> // // This library is free software; you can redistribute it and/or // modify it under the terms of the GNU Library General Public // License as published by the Free Software Foundation; either // version 2 of the License, or (at your option) any later version. // // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU // Library General Public License for more details. // // You should have received a copy of the GNU Library General Public // License along with this library; if not, write to the // Free Software Foundation, Inc., 59 Temple Place - Suite 330, // Boston, MA 02111-1307, USA. // // See the COPYING file located in the top-level-directory of // the archive of this library for complete text of license. */ package saffron.rel.plan; import openjava.ptree.Expression; import saffron.Planner; import saffron.opt.CallingConvention; import saffron.opt.Cluster; import saffron.opt.Cost; import saffron.opt.Implementor; import saffron.rel.Join; import saffron.rel.Rel; import saffron.runtime.Plan; import saffron.util.Util; /** * <code>PlanNestedLoopJoin</code> implements {@link Join} using the * nested-loop algorithm, with output as a {@link Plan}. * * <p>Nested-loops are the simplest implementation of a join: for each row * from the left hand side, get each row from the right hand side, apply * the condition, and return a joined row if the condition evaluates * true.</p> * * <p>A join isn't a relational expression as such. The output of a join * plan is an array of all of the objects which went into it. So, for * example, the output of <code>emp join (dept join division)</code> * contains 3 objects. **/ public class PlanNestedLoopJoin extends Join { public PlanNestedLoopJoin( Cluster cluster, Rel left, Rel right, Expression condition, int joinType) { super(cluster, left, right, condition, joinType); } // implement Rel public Object clone() { return new PlanNestedLoopJoin( cluster, Util.clone(left), Util.clone(right), Util.clone(condition), joinType); } // implement Plan public Cost computeSelfCost(Planner planner) { double dRows = left.getRows() * right.getRows() * Util.getSelectivity(condition), dCpu = left.getRows() * right.getRows(), dIo = 0; return planner.makeCost(dRows, dCpu, dIo); } // implement Rel public int getConvention() { return CallingConvention.PLAN; } public Object implement(Implementor implementor, int ordinal) { Plan leftPlan = (Plan) implementor.implementChild(this, 0, left), rightPlan = (Plan) implementor.implementChild(this, 1, right); Expression conditionPlan = implementExp( condition, new Plan[] {leftPlan, rightPlan}); return new NestedLoopJoinPlan( this, leftPlan, rightPlan, conditionPlan); } }
# | Change | User | Description | Committed | |
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#2 | 1474 | Julian Hyde |
saffron: Aggregations are working. Renamed 'aggregator' to 'aggregation'. |
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#1 | 1467 | Julian Hyde |
saffron: First saffron check-in; incorporate my changes to openjava. |