UnionNode.java

// 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.
// This file is copied from
// https://github.com/apache/impala/blob/branch-2.9.0/fe/src/main/java/org/apache/impala/UnionNode.java
// and modified by Doris

package org.apache.doris.planner;

import org.apache.doris.analysis.Expr;
import org.apache.doris.analysis.TupleId;
import org.apache.doris.statistics.StatisticalType;
import org.apache.doris.thrift.TPlanNode;
import org.apache.doris.thrift.TPlanNodeType;

import java.util.List;

public class UnionNode extends SetOperationNode {
    public UnionNode(PlanNodeId id, TupleId tupleId) {
        super(id, tupleId, "UNION", StatisticalType.UNION_NODE);
    }

    public UnionNode(PlanNodeId id, TupleId tupleId,
                        List<Expr> setOpResultExprs, boolean isInSubplan) {
        super(id, tupleId, "UNION", setOpResultExprs, isInSubplan, StatisticalType.UNION_NODE);
    }

    @Override
    protected void toThrift(TPlanNode msg) {
        toThrift(msg, TPlanNodeType.UNION_NODE);
    }

    // If it is a union without children which means it will output some constant values, we should use a serial union
    // to output non-duplicated data.
    @Override
    public boolean isSerialOperator() {
        return children.isEmpty();
    }
}