| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.pig.backend.hadoop.executionengine.mapReduceLayer; |
| |
| import java.util.List; |
| import java.util.LinkedList; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.plans.MROpPlanVisitor; |
| import org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.plans.MROperPlan; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhysicalPlan; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POFilter; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.ConstantExpression; |
| import org.apache.pig.impl.plan.DependencyOrderWalker; |
| import org.apache.pig.impl.plan.VisitorException; |
| import org.apache.pig.impl.util.Pair; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhyPlanVisitor; |
| |
| /** |
| * For historical reasons splits will always produce filters that pass |
| * everything through unchanged. This optimizer removes these. This |
| * optimizer is also a pre-req for the NoopStoreRemover. |
| * |
| * The condition we look for is POFilters with a constant boolean |
| * (true) expression as it's plan. |
| */ |
| class NoopFilterRemover extends MROpPlanVisitor { |
| |
| private Log log = LogFactory.getLog(getClass()); |
| |
| NoopFilterRemover(MROperPlan plan) { |
| super(plan, new DependencyOrderWalker<MapReduceOper, MROperPlan>(plan)); |
| } |
| |
| @Override |
| public void visitMROp(MapReduceOper mr) throws VisitorException { |
| new PhysicalRemover(mr.mapPlan).visit(); |
| new PhysicalRemover(mr.combinePlan).visit(); |
| new PhysicalRemover(mr.reducePlan).visit(); |
| } |
| |
| private class PhysicalRemover extends PhyPlanVisitor { |
| private List< Pair<POFilter, PhysicalPlan> > removalQ; |
| |
| PhysicalRemover(PhysicalPlan plan) { |
| super(plan, new DependencyOrderWalker<PhysicalOperator, PhysicalPlan>(plan)); |
| removalQ = new LinkedList< Pair<POFilter, PhysicalPlan> >(); |
| } |
| |
| @Override |
| public void visit() throws VisitorException { |
| super.visit(); |
| for (Pair<POFilter, PhysicalPlan> pair: removalQ) { |
| NoopFilterRemoverUtil.removeFilter(pair.first, pair.second); |
| } |
| removalQ.clear(); |
| } |
| |
| @Override |
| public void visitFilter(POFilter fl) throws VisitorException { |
| PhysicalPlan filterPlan = fl.getPlan(); |
| if (filterPlan.size() == 1) { |
| PhysicalOperator op = filterPlan.getRoots().get(0); |
| if (op instanceof ConstantExpression) { |
| ConstantExpression exp = (ConstantExpression)op; |
| Object value = exp.getValue(); |
| if (value instanceof Boolean) { |
| Boolean filterValue = (Boolean)value; |
| if (filterValue) { |
| removalQ.add(new Pair<POFilter, PhysicalPlan>(fl, mCurrentWalker.getPlan())); |
| } |
| } |
| } |
| } |
| } |
| } |
| } |