| /* |
| * 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.hyracks.algebricks.rewriter.rules; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.commons.lang3.mutable.Mutable; |
| import org.apache.commons.lang3.mutable.MutableObject; |
| |
| import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException; |
| import org.apache.hyracks.algebricks.common.utils.Triple; |
| import org.apache.hyracks.algebricks.core.algebra.base.ILogicalExpression; |
| import org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator; |
| import org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext; |
| import org.apache.hyracks.algebricks.core.algebra.base.LogicalOperatorTag; |
| import org.apache.hyracks.algebricks.core.algebra.base.LogicalVariable; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.UnionAllOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.UnnestOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.visitors.VariableUtilities; |
| import org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule; |
| |
| /** |
| * @author kereno, ecarm002, ildar.absalyamov |
| * Pushes down unnest through both branches of the union operator |
| * Before rule: |
| * ============ |
| * unnest |
| * union (left_branch, right_branch, res) |
| * left_branch |
| * right_branch |
| * After rule: |
| * ============ |
| * union (left_branch, right_branch, res) |
| * unnest |
| * left_branch |
| * unnest |
| * right_branch |
| */ |
| public class PushUnnestDownThroughUnionRule implements IAlgebraicRewriteRule { |
| |
| @Override |
| public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context) { |
| return false; |
| } |
| |
| @Override |
| public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context) |
| throws AlgebricksException { |
| |
| AbstractLogicalOperator unnest = (AbstractLogicalOperator) opRef.getValue(); |
| if (unnest.getOperatorTag() != LogicalOperatorTag.UNNEST) { |
| return false; |
| } |
| UnnestOperator unnestOpRef = (UnnestOperator) opRef.getValue(); |
| Mutable<ILogicalOperator> unionOp = unnest.getInputs().get(0); |
| |
| AbstractLogicalOperator unionAbstractOp = (AbstractLogicalOperator) unionOp.getValue(); |
| if (unionAbstractOp.getOperatorTag() != LogicalOperatorTag.UNIONALL) { |
| return false; |
| } |
| |
| LogicalVariable unnestVar1 = context.newVar(); |
| UnnestOperator unnest1 = new UnnestOperator(unnestVar1, new MutableObject<ILogicalExpression>(unnestOpRef |
| .getExpressionRef().getValue().cloneExpression())); |
| LogicalVariable unnestVar2 = context.newVar(); |
| UnnestOperator unnest2 = new UnnestOperator(unnestVar2, new MutableObject<ILogicalExpression>(unnestOpRef |
| .getExpressionRef().getValue().cloneExpression())); |
| |
| //Getting the two topmost branched and adding them as an input to the unnests: |
| Mutable<ILogicalOperator> branch1 = unionAbstractOp.getInputs().get(0); |
| ILogicalOperator agg1 = branch1.getValue(); |
| List<LogicalVariable> agg1_var = new ArrayList<LogicalVariable>(); |
| VariableUtilities.getLiveVariables(agg1, agg1_var); |
| Mutable<ILogicalOperator> branch2 = unionAbstractOp.getInputs().get(1); |
| ILogicalOperator agg2 = branch2.getValue(); |
| List<LogicalVariable> agg2_var = new ArrayList<LogicalVariable>(); |
| VariableUtilities.getLiveVariables(agg2, agg2_var); |
| |
| //Modifying the unnest so it has the right variable |
| List<LogicalVariable> var_unnest_1 = new ArrayList<LogicalVariable>(); |
| unnest1.getExpressionRef().getValue().getUsedVariables(var_unnest_1); |
| unnest1.getExpressionRef().getValue().substituteVar(var_unnest_1.get(0), agg1_var.get(0)); |
| |
| List<LogicalVariable> var_unnest2 = new ArrayList<LogicalVariable>(); |
| unnest2.getExpressionRef().getValue().getUsedVariables(var_unnest2); |
| unnest2.getExpressionRef().getValue().substituteVar(var_unnest2.get(0), agg2_var.get(0)); |
| |
| unnest1.getInputs().add(branch1); |
| unnest2.getInputs().add(branch2); |
| context.computeAndSetTypeEnvironmentForOperator(unnest1); |
| context.computeAndSetTypeEnvironmentForOperator(unnest2); |
| |
| //creating a new union operator with the updated logical variables |
| List<Triple<LogicalVariable, LogicalVariable, LogicalVariable>> varMap = new ArrayList<Triple<LogicalVariable, LogicalVariable, LogicalVariable>>( |
| 1); |
| Triple<LogicalVariable, LogicalVariable, LogicalVariable> union_triple_vars = new Triple<LogicalVariable, LogicalVariable, LogicalVariable>( |
| unnestVar1, unnestVar2, unnestOpRef.getVariables().get(0)); |
| varMap.add(union_triple_vars); |
| UnionAllOperator unionOpFinal = new UnionAllOperator(varMap); |
| |
| unionOpFinal.getInputs().add(new MutableObject<ILogicalOperator>(unnest1)); |
| unionOpFinal.getInputs().add(new MutableObject<ILogicalOperator>(unnest2)); |
| |
| context.computeAndSetTypeEnvironmentForOperator(unionOpFinal); |
| |
| opRef.setValue(unionOpFinal); |
| return true; |
| |
| } |
| } |