| /* |
| * 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.ArrayList; |
| import java.util.List; |
| |
| import org.apache.commons.lang3.mutable.Mutable; |
| 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.operators.logical.AbstractLogicalOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.AssignOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.DataSourceScanOperator; |
| import org.apache.hyracks.algebricks.core.algebra.operators.logical.UnnestOperator; |
| import org.apache.vxquery.compiler.rewriter.VXQueryOptimizationContext; |
| import org.apache.vxquery.compiler.rewriter.rules.util.ExpressionToolbox; |
| import org.apache.vxquery.context.StaticContext; |
| import org.apache.vxquery.functions.BuiltinOperators; |
| import org.apache.vxquery.metadata.VXQueryCollectionDataSource; |
| import org.apache.vxquery.metadata.VXQueryIndexingDataSource; |
| import org.apache.vxquery.metadata.VXQueryMetadataProvider; |
| import org.apache.vxquery.types.ElementType; |
| |
| /** |
| * The rule searches for an unnest operator immediately following a data scan |
| * operator. |
| * |
| * <pre> |
| * Before |
| * |
| * plan__parent |
| * UNNEST( $v2 : child( $v1 ) ) |
| * DATASCAN( $source : $v1 ) |
| * plan__child |
| * |
| * Where $v1 is not used in plan__parent. |
| * |
| * After |
| * |
| * plan__parent |
| * DATASCAN( $source : $v1 ) |
| * plan__child |
| * |
| * $source is encoded with the child parameters. |
| * </pre> |
| * |
| * @author prestonc |
| */ |
| public class PushChildIntoDataScanRule extends AbstractUsedVariablesProcessingRule { |
| StaticContext dCtx = null; |
| final int ARG_DATA = 0; |
| final int ARG_TYPE = 1; |
| |
| protected boolean processOperator(Mutable<ILogicalOperator> opRef, IOptimizationContext context) |
| throws AlgebricksException { |
| if (dCtx == null) { |
| VXQueryOptimizationContext vxqueryCtx = (VXQueryOptimizationContext) context; |
| dCtx = ((VXQueryMetadataProvider) vxqueryCtx.getMetadataProvider()).getStaticContext(); |
| } |
| AbstractLogicalOperator op1 = (AbstractLogicalOperator) opRef.getValue(); |
| if (op1.getOperatorTag() != LogicalOperatorTag.UNNEST) { |
| return false; |
| } |
| UnnestOperator unnest = (UnnestOperator) op1; |
| |
| AbstractLogicalOperator op2 = (AbstractLogicalOperator) unnest.getInputs().get(0).getValue(); |
| if (op2.getOperatorTag() != LogicalOperatorTag.DATASOURCESCAN) { |
| return false; |
| } |
| DataSourceScanOperator datascan = (DataSourceScanOperator) op2; |
| |
| if (!usedVariables.contains(datascan.getVariables())) { |
| VXQueryCollectionDataSource ds = null; |
| VXQueryIndexingDataSource ids = null; |
| |
| // Find all child functions. |
| try { |
| ids = (VXQueryIndexingDataSource) datascan.getDataSource(); |
| } catch (ClassCastException e) { |
| ds = (VXQueryCollectionDataSource) datascan.getDataSource(); |
| } |
| |
| if (!updateDataSource(ds, unnest.getExpressionRef())) { |
| return false; |
| } |
| |
| // Replace unnest with noop assign. Keeps variable chain. |
| Mutable<ILogicalExpression> varExp = ExpressionToolbox.findVariableExpression(unnest.getExpressionRef(), |
| datascan.getVariables().get(0)); |
| AssignOperator noOp = new AssignOperator(unnest.getVariable(), varExp); |
| noOp.getInputs().addAll(unnest.getInputs()); |
| opRef.setValue(noOp); |
| return true; |
| } |
| return false; |
| } |
| |
| /** |
| * In reverse add them to the data source. |
| * |
| * @param ds |
| * @param expression |
| */ |
| private boolean updateDataSource(VXQueryCollectionDataSource ds, Mutable<ILogicalExpression> expression) { |
| boolean added = false; |
| List<Mutable<ILogicalExpression>> finds = new ArrayList<Mutable<ILogicalExpression>>(); |
| ExpressionToolbox.findAllFunctionExpressions(expression, BuiltinOperators.CHILD.getFunctionIdentifier(), finds); |
| for (int i = finds.size(); i > 0; --i) { |
| int typeId = ExpressionToolbox.getTypeExpressionTypeArgument(finds.get(i - 1)); |
| if (typeId > 0) { |
| if (dCtx.lookupSequenceType(typeId).getItemType().equals(ElementType.ANYELEMENT) && typeId > 0) { |
| ds.addChildSeq(typeId); |
| added = true; |
| } |
| } |
| } |
| return added; |
| } |
| } |