| /** |
| * 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.tajo.engine.planner.physical; |
| |
| import org.apache.tajo.plan.logical.JoinNode; |
| import org.apache.tajo.storage.Tuple; |
| import org.apache.tajo.worker.TaskAttemptContext; |
| |
| import java.io.IOException; |
| import java.util.List; |
| |
| /** |
| * Prepare a hash table of the NOT IN side of the join. Scan the FROM side table. |
| * For each tuple of the FROM side table, it tries to find a matched tuple from the hash table for the NOT INT side. |
| * If not found, it returns the tuple of the FROM side table with null padding. |
| */ |
| public class HashLeftAntiJoinExec extends HashJoinExec { |
| |
| private final List<Tuple> nullTupleList = nullTupleList(0); |
| |
| public HashLeftAntiJoinExec(TaskAttemptContext context, JoinNode plan, PhysicalExec fromSideChild, |
| PhysicalExec notInSideChild) { |
| super(context, plan, fromSideChild, notInSideChild); |
| } |
| |
| /** |
| * The End of Tuple (EOT) condition is true only when no more tuple in the left relation (on disk). |
| * next() method finds the first unmatched tuple from both tables. |
| * |
| * For each left tuple, next() tries to find the right tuple from the hash table. If there is no hash bucket |
| * in the hash table. It returns a tuple. If next() find the hash bucket in the hash table, it reads tuples in |
| * the found bucket sequentially. If it cannot find tuple in the bucket, it returns a tuple. |
| * |
| * @return The tuple which is unmatched to a given join condition. |
| * @throws IOException |
| */ |
| @Override |
| public Tuple next() throws IOException { |
| if (first) { |
| loadRightToHashTable(); |
| } |
| |
| while(!context.isStopped() && !finished) { |
| if (iterator != null && iterator.hasNext()) { |
| frameTuple.setRight(iterator.next()); |
| return projector.eval(frameTuple); |
| } |
| // getting new outer |
| Tuple leftTuple = leftChild.next(); // it comes from a disk |
| if (leftTuple == null || leftFiltered(leftTuple)) { // if no more tuples in left tuples on disk, a join is completed. |
| finished = leftTuple == null; |
| continue; |
| } |
| |
| frameTuple.setLeft(leftTuple); |
| |
| // Try to find a hash bucket in in-memory hash table |
| TupleList hashed = tupleSlots.get(leftKeyExtractor.project(leftTuple)); |
| if (hashed == null || !rightFiltered(hashed).hasNext()) { |
| iterator = nullTupleList.iterator(); |
| } |
| } |
| return null; |
| } |
| } |