| /* |
| * 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 org.apache.commons.lang3.mutable.Mutable; |
| import org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator; |
| import org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext; |
| import org.apache.vxquery.common.VXQueryCommons; |
| import org.apache.vxquery.compiler.rewriter.VXQueryOptimizationContext; |
| import org.apache.vxquery.metadata.VXQueryCollectionDataSource; |
| import org.apache.vxquery.types.AnyItemType; |
| import org.apache.vxquery.types.Quantifier; |
| import org.apache.vxquery.types.SequenceType; |
| |
| /** |
| * Find the default query plan created for collection and updated it to use |
| * parallelization. The rule searches for unnest followed by an assign for the |
| * collection function expression. When this plan block exists the data source |
| * scan operator added in the blocks place. |
| * |
| * <pre> |
| * Before |
| * |
| * plan__parent |
| * UNNEST( $v2 : exp($v1) ) |
| * ASSIGN( $v1 : collection( $v0 ) ) |
| * ASSIGN( $v0 : constant ) |
| * plan__child |
| * |
| * After |
| * |
| * plan__parent |
| * UNNEST( $v2 : exp($v1) ) |
| * DATASCAN( collection( $v0 ) , $v1 ) |
| * plan__child |
| * |
| * Where DATASCAN operator is configured to use the collection( $v0) for |
| * data represented by the "constant" and $v1 represents the xml document |
| * nodes from the collection. |
| * </pre> |
| * |
| * @author prestonc |
| */ |
| public class IntroduceCollectionRule extends AbstractCollectionRule { |
| |
| @Override |
| public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context) { |
| VXQueryOptimizationContext vxqueryContext = (VXQueryOptimizationContext) context; |
| String[] args = getFunctionalArguments(opRef, VXQueryCommons.collectionFunctions); |
| |
| if (args != null) { |
| String collectionName = args[0]; |
| // Build the new operator and update the query plan. |
| int collectionId = vxqueryContext.newCollectionId(); |
| VXQueryCollectionDataSource ds = VXQueryCollectionDataSource.create(collectionId, collectionName, |
| SequenceType.create(AnyItemType.INSTANCE, Quantifier.QUANT_STAR)); |
| if (ds != null) { |
| ds.setTotalDataSources(vxqueryContext.getTotalDataSources()); |
| |
| // Check if the call is for collection-with-tag |
| if (args.length == 2) { |
| ds.setTotalDataSources(vxqueryContext.getTotalDataSources()); |
| ds.setTag(args[1]); |
| } |
| |
| // Known to be true because of collection name. |
| return setDataSourceScan(ds, opRef); |
| } |
| } |
| return false; |
| } |
| |
| } |