| /* |
| * 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.HashSet; |
| import java.util.List; |
| import java.util.Set; |
| |
| 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.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.expressions.ConstantExpression; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.AbstractScanOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.EmptyTupleSourceOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.InnerJoinOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.visitors.VariableUtilities; |
| import org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule; |
| |
| public class SimpleUnnestToProductRule 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 op = (AbstractLogicalOperator) opRef.getValue(); |
| if (op.getOperatorTag() != LogicalOperatorTag.DATASOURCESCAN |
| && op.getOperatorTag() != LogicalOperatorTag.UNNEST) { |
| return false; |
| } |
| |
| Mutable<ILogicalOperator> opRef2 = op.getInputs().get(0); |
| AbstractLogicalOperator op2 = (AbstractLogicalOperator) opRef2.getValue(); |
| |
| if (!(op2 instanceof AbstractScanOperator) && !descOrSelfIsSourceScan(op2)) { |
| return false; |
| } |
| // Make sure that op does not use any variables produced by op2. |
| if (!opsAreIndependent(op, op2)) { |
| return false; |
| } |
| |
| /** |
| * finding the boundary between left branch and right branch |
| * operator pipeline on-top-of boundaryOpRef (exclusive) is the inner branch |
| * operator pipeline under boundaryOpRef (inclusive) is the outer branch |
| */ |
| Mutable<ILogicalOperator> currentOpRef = opRef; |
| Mutable<ILogicalOperator> boundaryOpRef = currentOpRef.getValue().getInputs().get(0); |
| while (currentOpRef.getValue().getInputs().size() == 1) { |
| currentOpRef = currentOpRef.getValue().getInputs().get(0); |
| } |
| Mutable<ILogicalOperator> tupleSourceOpRef = currentOpRef; |
| currentOpRef = opRef; |
| if (tupleSourceOpRef.getValue().getOperatorTag() == LogicalOperatorTag.NESTEDTUPLESOURCE) { |
| while (currentOpRef.getValue().getInputs().size() == 1 |
| /* |
| * When this rule is fired, |
| * Unnests with a dataset function have been rewritten to DataSourceScans and |
| * AccessMethod related rewriting hasn't been done. Therefore, we only need |
| * to check if currentOpRef holds a DataSourceScanOperator. |
| */ |
| && currentOpRef.getValue().getOperatorTag() == LogicalOperatorTag.DATASOURCESCAN |
| && descOrSelfIsSourceScan((AbstractLogicalOperator) currentOpRef.getValue())) { |
| if (opsAreIndependent(currentOpRef.getValue(), tupleSourceOpRef.getValue())) { |
| /** move down the boundary if the operator is independent of the tuple source */ |
| boundaryOpRef = currentOpRef.getValue().getInputs().get(0); |
| } else { |
| break; |
| } |
| currentOpRef = currentOpRef.getValue().getInputs().get(0); |
| } |
| } else { |
| //Move the boundary below any top const assigns. |
| boundaryOpRef = opRef.getValue().getInputs().get(0); |
| while (boundaryOpRef.getValue().getInputs().size() == 1 |
| /* |
| * When this rule is fired, |
| * Unnests with a dataset function have been rewritten to DataSourceScans and |
| * AccessMethod related rewriting hasn't been done. Therefore, we only need |
| * to check if boundaryOpRef holds a DataSourceScanOperator. |
| */ |
| && boundaryOpRef.getValue().getOperatorTag() != LogicalOperatorTag.DATASOURCESCAN) { |
| List<LogicalVariable> opUsedVars = new ArrayList<LogicalVariable>(); |
| VariableUtilities.getUsedVariables(boundaryOpRef.getValue(), opUsedVars); |
| if (opUsedVars.size() == 0) { |
| // move down the boundary if the operator is a const assigns. |
| boundaryOpRef = boundaryOpRef.getValue().getInputs().get(0); |
| } else { |
| break; |
| } |
| } |
| } |
| |
| /** join the two independent branches */ |
| InnerJoinOperator join = new InnerJoinOperator(new MutableObject<ILogicalExpression>(ConstantExpression.TRUE), |
| new MutableObject<ILogicalOperator>(boundaryOpRef.getValue()), |
| new MutableObject<ILogicalOperator>(opRef.getValue())); |
| opRef.setValue(join); |
| ILogicalOperator ets = new EmptyTupleSourceOperator(); |
| context.computeAndSetTypeEnvironmentForOperator(ets); |
| boundaryOpRef.setValue(ets); |
| context.computeAndSetTypeEnvironmentForOperator(boundaryOpRef.getValue()); |
| context.computeAndSetTypeEnvironmentForOperator(opRef.getValue()); |
| context.computeAndSetTypeEnvironmentForOperator(join); |
| return true; |
| } |
| |
| private boolean descOrSelfIsSourceScan(AbstractLogicalOperator op2) { |
| // Disregard data source scans in a subplan. |
| if (op2.getOperatorTag() == LogicalOperatorTag.SUBPLAN) { |
| return false; |
| } |
| if (op2.getOperatorTag() == LogicalOperatorTag.DATASOURCESCAN |
| && op2.getOperatorTag() != LogicalOperatorTag.UNNEST) { |
| return true; |
| } |
| for (Mutable<ILogicalOperator> cRef : op2.getInputs()) { |
| AbstractLogicalOperator alo = (AbstractLogicalOperator) cRef.getValue(); |
| if (descOrSelfIsSourceScan(alo)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| private boolean opsAreIndependent(ILogicalOperator unnestOp, ILogicalOperator outer) throws AlgebricksException { |
| if (unnestOp.equals(outer)) { |
| return false; |
| } |
| List<LogicalVariable> opUsedVars = new ArrayList<LogicalVariable>(); |
| VariableUtilities.getUsedVariables(unnestOp, opUsedVars); |
| Set<LogicalVariable> op2LiveVars = new HashSet<LogicalVariable>(); |
| VariableUtilities.getLiveVariables(outer, op2LiveVars); |
| for (LogicalVariable usedVar : opUsedVars) { |
| if (op2LiveVars.contains(usedVar)) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| } |