| /* |
| * 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; |
| |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.apache.commons.lang3.mutable.Mutable; |
| import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException; |
| import org.apache.hyracks.algebricks.common.utils.Pair; |
| 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.LogicalExpressionTag; |
| import org.apache.hyracks.algebricks.core.algebra.base.LogicalOperatorTag; |
| import org.apache.hyracks.algebricks.core.algebra.expressions.AbstractFunctionCallExpression; |
| import org.apache.hyracks.algebricks.core.algebra.expressions.AggregateFunctionCallExpression; |
| import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier; |
| import org.apache.hyracks.algebricks.core.algebra.functions.IFunctionInfo; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.AggregateOperator; |
| import org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule; |
| import org.apache.vxquery.functions.BuiltinFunctions; |
| import org.apache.vxquery.functions.BuiltinOperators; |
| |
| /** |
| * The rule searches for aggregate operators with an aggregate function |
| * expression that has not been initialized for two step aggregation. |
| * |
| * <pre> |
| * Before |
| * |
| * plan__parent |
| * AGGREGATE( $v : af1( $v1 ) ) |
| * plan__child |
| * |
| * Where af1 is a VXquery aggregate function expression configured for single |
| * step processing and $v1 is defined in plan__child. |
| * |
| * After |
| * |
| * if (af1 == count) aggregate operating settings: |
| * Step 1: count |
| * Step 2: sum |
| * if (af1 == avg) aggregate operating settings: |
| * Step 1: avg-local |
| * Step 2: avg-global |
| * if (af1 in (max, min, sum)) aggregate operating settings: |
| * Step 1: af1 |
| * Step 2: af1 |
| * </pre> |
| * |
| * @author prestonc |
| */ |
| public class IntroduceTwoStepAggregateRule implements IAlgebraicRewriteRule { |
| final Map<FunctionIdentifier, Pair<IFunctionInfo, IFunctionInfo>> AGGREGATE_MAP = new HashMap<FunctionIdentifier, Pair<IFunctionInfo, IFunctionInfo>>(); |
| |
| public IntroduceTwoStepAggregateRule() { |
| AGGREGATE_MAP.put(BuiltinFunctions.FN_AVG_1.getFunctionIdentifier(), |
| new Pair<IFunctionInfo, IFunctionInfo>(BuiltinOperators.AVG_LOCAL, BuiltinOperators.AVG_GLOBAL)); |
| AGGREGATE_MAP.put(BuiltinFunctions.FN_COUNT_1.getFunctionIdentifier(), |
| new Pair<IFunctionInfo, IFunctionInfo>(BuiltinFunctions.FN_COUNT_1, BuiltinFunctions.FN_SUM_1)); |
| AGGREGATE_MAP.put(BuiltinFunctions.FN_MAX_1.getFunctionIdentifier(), |
| new Pair<IFunctionInfo, IFunctionInfo>(BuiltinFunctions.FN_MAX_1, BuiltinFunctions.FN_MAX_1)); |
| AGGREGATE_MAP.put(BuiltinFunctions.FN_MIN_1.getFunctionIdentifier(), |
| new Pair<IFunctionInfo, IFunctionInfo>(BuiltinFunctions.FN_MIN_1, BuiltinFunctions.FN_MIN_1)); |
| AGGREGATE_MAP.put(BuiltinFunctions.FN_SUM_1.getFunctionIdentifier(), |
| new Pair<IFunctionInfo, IFunctionInfo>(BuiltinFunctions.FN_SUM_1, BuiltinFunctions.FN_SUM_1)); |
| } |
| |
| @Override |
| public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context) |
| throws AlgebricksException { |
| // Check if aggregate function. |
| AbstractLogicalOperator op = (AbstractLogicalOperator) opRef.getValue(); |
| if (op.getOperatorTag() != LogicalOperatorTag.AGGREGATE) { |
| return false; |
| } |
| final AggregateOperator aggregate = (AggregateOperator) op; |
| AggregateFunctionCallExpression aggregateFunctionCall = getAggregateFunctionCall(aggregate); |
| if (aggregateFunctionCall == null || aggregateFunctionCall.isTwoStep()) { |
| return false; |
| } |
| // Replace single step aggregate function with two step function call |
| final IFunctionInfo functionInfo = aggregateFunctionCall.getFunctionInfo(); |
| final List<Mutable<ILogicalExpression>> arguments = aggregateFunctionCall.getArguments(); |
| AggregateFunctionCallExpression twoStepCall = |
| new AggregateFunctionCallExpression(functionInfo, true, arguments); |
| final Pair<IFunctionInfo, IFunctionInfo> functionInfoPair = |
| AGGREGATE_MAP.get(aggregateFunctionCall.getFunctionIdentifier()); |
| twoStepCall.setStepOneAggregate(functionInfoPair.first); |
| twoStepCall.setStepTwoAggregate(functionInfoPair.second); |
| aggregate.getExpressions().get(0).setValue(twoStepCall); |
| return true; |
| } |
| |
| private AggregateFunctionCallExpression getAggregateFunctionCall(AggregateOperator aggregate) { |
| if (aggregate.getExpressions().size() == 0) { |
| return null; |
| } |
| ILogicalExpression logicalExpression = aggregate.getExpressions().get(0).getValue(); |
| if (logicalExpression.getExpressionTag() != LogicalExpressionTag.FUNCTION_CALL) { |
| return null; |
| } |
| AbstractFunctionCallExpression functionCall = (AbstractFunctionCallExpression) logicalExpression; |
| if (AGGREGATE_MAP.containsKey(functionCall.getFunctionIdentifier())) { |
| return (AggregateFunctionCallExpression) functionCall; |
| } |
| return null; |
| } |
| |
| @Override |
| public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context) { |
| return false; |
| } |
| } |