org.apache.drill.exec.planner.cost.DrillRelMdRowCount Maven / Gradle / Ivy

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package org.apache.drill.exec.planner.cost;

import org.apache.calcite.rel.core.Aggregate;
import org.apache.calcite.rel.metadata.ReflectiveRelMetadataProvider;
import org.apache.calcite.rel.metadata.RelMdRowCount;
import org.apache.calcite.rel.metadata.RelMetadataProvider;
import org.apache.calcite.util.BuiltInMethod;
import org.apache.calcite.util.ImmutableBitSet;

public class DrillRelMdRowCount extends RelMdRowCount{
  private static final DrillRelMdRowCount INSTANCE = new DrillRelMdRowCount();

  public static final RelMetadataProvider SOURCE = ReflectiveRelMetadataProvider.reflectiveSource(BuiltInMethod.ROW_COUNT.method, INSTANCE);

  @Override
  public Double getRowCount(Aggregate rel) {
    ImmutableBitSet groupKey = ImmutableBitSet.range(rel.getGroupCount());

    if (groupKey.isEmpty()) {
      return 1.0;
    } else {
      return super.getRowCount(rel);
    }
  }
}