| // 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.impala.planner; |
| |
| import org.apache.impala.analysis.Analyzer; |
| import org.apache.impala.common.ImpalaException; |
| import org.apache.impala.thrift.TCardinalityCheckNode; |
| import org.apache.impala.thrift.TExplainLevel; |
| import org.apache.impala.thrift.TPlanNode; |
| import org.apache.impala.thrift.TPlanNodeType; |
| import org.apache.impala.thrift.TQueryOptions; |
| |
| import com.google.common.base.Preconditions; |
| |
| /** |
| * Node that returns an error if its child produces more than a single row. |
| * If successful, this node returns a deep copy of its single input row. |
| * |
| * Note that this node must be a blocking node. It would be incorrect to return rows |
| * before the single row constraint has been validated because downstream exec nodes |
| * might produce results and incorrectly return them to the client. If the child of this |
| * node produces more than one row it means the SQL query is semantically invalid, so no |
| * rows must be returned to the client. |
| */ |
| public class CardinalityCheckNode extends PlanNode { |
| private final String displayStatement_; |
| |
| protected CardinalityCheckNode(PlanNodeId id, PlanNode child, String displayStmt) { |
| super(id, "CARDINALITY CHECK"); |
| Preconditions.checkState(child.getLimit() <= 2); |
| cardinality_ = 1; |
| limit_ = 1; |
| displayStatement_ = displayStmt; |
| addChild(child); |
| computeTupleIds(); |
| } |
| |
| /** |
| * Same as PlanNode.init(), except we don't assign conjuncts. |
| */ |
| @Override |
| public void init(Analyzer analyzer) throws ImpalaException { |
| computeStats(analyzer); |
| createDefaultSmap(analyzer); |
| } |
| |
| @Override |
| public boolean isBlockingNode() { return true; } |
| |
| @Override |
| public void computeTupleIds() { |
| clearTupleIds(); |
| tblRefIds_.addAll(getChild(0).getTblRefIds()); |
| tupleIds_.addAll(getChild(0).getTupleIds()); |
| nullableTupleIds_.addAll(getChild(0).getNullableTupleIds()); |
| } |
| |
| @Override |
| protected void toThrift(TPlanNode msg) { |
| msg.node_type = TPlanNodeType.CARDINALITY_CHECK_NODE; |
| TCardinalityCheckNode cardinalityCheckNode = new TCardinalityCheckNode( |
| displayStatement_); |
| msg.setCardinality_check_node(cardinalityCheckNode); |
| } |
| |
| @Override |
| public void computeNodeResourceProfile(TQueryOptions queryOptions) { |
| nodeResourceProfile_ = ResourceProfile.noReservation(0); |
| } |
| |
| @Override |
| protected String getNodeExplainString(String prefix, String detailPrefix, |
| TExplainLevel detailLevel) { |
| return String.format("%s%s:%s\n", prefix, id_.toString(), displayName_); |
| } |
| } |