| /* |
| * 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.vxquery.compiler.rewriter.rules.algebricksalternatives; |
| |
| import java.util.HashSet; |
| import java.util.ListIterator; |
| import java.util.Set; |
| |
| import org.apache.commons.lang3.mutable.Mutable; |
| |
| import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException; |
| import org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator; |
| import org.apache.hyracks.algebricks.core.algebra.base.ILogicalPlan; |
| 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.SubplanOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.visitors.VariableUtilities; |
| import org.apache.hyracks.algebricks.core.algebra.util.OperatorPropertiesUtil; |
| import org.apache.hyracks.algebricks.rewriter.rules.AbstractDecorrelationRule; |
| |
| /** |
| * The rule searches for operators that can be moved outside the subplan. |
| * |
| * <pre> |
| * Before |
| * |
| * %PARENT_PLAN |
| * SUBPLAN{ |
| * %NESTED_OPERATORS_B+ |
| * ASSIGN || %SUBPLAN |
| * %NESTED_OPERATORS_A* |
| * NESTEDTUPLESOURCE |
| * } |
| * %CHILD_PLAN |
| * |
| * where |
| * %SUBPLAN has one nested plan with a root AGGREGATE operator. |
| * |
| * After |
| * |
| * %PARENT_PLAN |
| * SUBPLAN{ |
| * %NESTED_OPERATORS_B+ |
| * %NESTED_OPERATORS_A* |
| * NESTEDTUPLESOURCE |
| * } |
| * ASSIGN || %SUBPLAN |
| * %CHILD_PLAN |
| * </pre> |
| */ |
| public class MoveFreeVariableOperatorOutOfSubplanRule extends AbstractDecorrelationRule { |
| |
| @Override |
| public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context) |
| throws AlgebricksException { |
| AbstractLogicalOperator op0 = (AbstractLogicalOperator) opRef.getValue(); |
| if (op0.getOperatorTag() != LogicalOperatorTag.SUBPLAN) { |
| return false; |
| } |
| SubplanOperator subplan = (SubplanOperator) op0; |
| |
| Mutable<ILogicalOperator> leftRef = subplan.getInputs().get(0); |
| if (((AbstractLogicalOperator) leftRef.getValue()).getOperatorTag() == LogicalOperatorTag.EMPTYTUPLESOURCE) { |
| return false; |
| } |
| |
| ListIterator<ILogicalPlan> plansIter = subplan.getNestedPlans().listIterator(); |
| ILogicalPlan p = null; |
| while (plansIter.hasNext()) { |
| p = plansIter.next(); |
| } |
| if (p == null) { |
| return false; |
| } |
| if (p.getRoots().size() != 1) { |
| return false; |
| } |
| Mutable<ILogicalOperator> opRef1 = p.getRoots().get(0); |
| |
| //The root operator will not be movable. Start with the second op |
| AbstractLogicalOperator op1 = (AbstractLogicalOperator) opRef1.getValue(); |
| if (op1.getInputs().size() != 1) { |
| return false; |
| } |
| Mutable<ILogicalOperator> op2Ref = op1.getInputs().get(0); |
| |
| //Get all variables that come from outside of the loop |
| Set<LogicalVariable> free = new HashSet<LogicalVariable>(); |
| OperatorPropertiesUtil.getFreeVariablesInSelfOrDesc(op1, free); |
| |
| while (op2Ref != null) { |
| //Get the operator that we want to look at |
| AbstractLogicalOperator op2 = (AbstractLogicalOperator) op2Ref.getValue(); |
| |
| //Make sure we are looking at subplan with a scan/join |
| if (op2.getInputs().size() != 1 || !descOrSelfIsScanOrJoin(op2)) { |
| return false; |
| } |
| boolean notApplicable = false; |
| |
| //Get its used variables |
| Set<LogicalVariable> used = new HashSet<LogicalVariable>(); |
| |
| //not movable if the operator is not an assign or subplan |
| //Might be helpful in the future for other operations in the future |
| if (op2.getOperatorTag() == LogicalOperatorTag.ASSIGN) { |
| VariableUtilities.getUsedVariables(op2, used); |
| } else if (op2.getOperatorTag() == LogicalOperatorTag.SUBPLAN) { |
| // Nested plan must have an aggregate root. |
| ListIterator<ILogicalPlan> subplansIter = ((SubplanOperator) op2).getNestedPlans().listIterator(); |
| ILogicalPlan plan = null; |
| while (subplansIter.hasNext()) { |
| plan = subplansIter.next(); |
| } |
| if (plan == null) { |
| return false; |
| } |
| if (plan.getRoots().size() != 1) { |
| return false; |
| } |
| ILogicalOperator op3 = plan.getRoots().get(0).getValue(); |
| if (op3.getOperatorTag() != LogicalOperatorTag.AGGREGATE) { |
| return false; |
| } |
| // Used variables do not include ones created in the subplan. |
| VariableUtilities.getUsedVariables(op2, used); |
| Set<LogicalVariable> subplanProducedAndDown = new HashSet<LogicalVariable>(); |
| VariableUtilities.getProducedVariablesInDescendantsAndSelf(op3, subplanProducedAndDown); |
| used.removeAll(subplanProducedAndDown); |
| } else { |
| notApplicable = true; |
| } |
| |
| //Make sure that all of its used variables come from outside |
| for (LogicalVariable var : used) { |
| if (!free.contains(var)) { |
| notApplicable = true; |
| } |
| } |
| |
| if (notApplicable) { |
| op2Ref = op2.getInputs().get(0); |
| } else { |
| //Make the input of op2 be the input of op1 |
| op2Ref.setValue(op2.getInputs().get(0).getValue()); |
| |
| //Make the outside of the subplan the input of op2 |
| Mutable<ILogicalOperator> outsideRef = op2.getInputs().get(0); |
| outsideRef.setValue(op0.getInputs().get(0).getValue()); |
| |
| //Make op2 the input of the subplan |
| Mutable<ILogicalOperator> op2OutsideRef = op0.getInputs().get(0); |
| op2OutsideRef.setValue(op2); |
| |
| return true; |
| } |
| |
| } |
| return false; |
| } |
| |
| } |