exec/java-exec/src/main/java/org/apache/drill/exec/planner/common/DrillScreenRelBase.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.
 */
package org.apache.drill.exec.planner.common;

import org.apache.drill.exec.planner.cost.DrillCostBase.DrillCostFactory;
import org.apache.drill.exec.planner.physical.PrelUtil;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.SingleRel;
import org.apache.calcite.rel.metadata.RelMetadataQuery;
import org.apache.calcite.plan.Convention;
import org.apache.calcite.plan.RelOptCluster;
import org.apache.calcite.plan.RelOptCost;
import org.apache.calcite.plan.RelOptPlanner;
import org.apache.calcite.plan.RelTraitSet;

/**
 * Base class for logical and physical Screen implemented in Drill
 */
public abstract class DrillScreenRelBase extends SingleRel implements DrillRelNode {

  public DrillScreenRelBase(Convention convention, RelOptCluster cluster, RelTraitSet traitSet, RelNode input) {
    super(cluster, traitSet, input);
    assert input.getConvention() == convention;
  }

  @Override
  public RelOptCost computeSelfCost(RelOptPlanner planner, RelMetadataQuery mq) {
    if(PrelUtil.getSettings(getCluster()).useDefaultCosting()) {
      return super.computeSelfCost(planner, mq).multiplyBy(.1);
    }
    // by default, assume cost is proportional to number of rows
    double rowCount = mq.getRowCount(this);
    DrillCostFactory costFactory = (DrillCostFactory)planner.getCostFactory();
    return costFactory.makeCost(rowCount, rowCount, 0, 0).multiplyBy(0.1);
  }

}