org.apache.hadoop.hive.ql.optimizer.calcite.cost.HiveDefaultCostModel Maven / Gradle / Ivy
/**
* 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.hadoop.hive.ql.optimizer.calcite.cost;
import org.apache.calcite.plan.RelOptCost;
import org.apache.calcite.rel.RelCollation;
import org.apache.calcite.rel.RelDistribution;
import org.apache.calcite.rel.metadata.RelMetadataQuery;
import org.apache.hadoop.hive.ql.optimizer.calcite.reloperators.HiveAggregate;
import org.apache.hadoop.hive.ql.optimizer.calcite.reloperators.HiveJoin;
import org.apache.hadoop.hive.ql.optimizer.calcite.reloperators.HiveTableScan;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Sets;
/**
* Default implementation of the cost model.
* Currently used by MR and Spark execution engines.
*/
public class HiveDefaultCostModel extends HiveCostModel {
private static HiveDefaultCostModel INSTANCE;
synchronized public static HiveDefaultCostModel getCostModel() {
if (INSTANCE == null) {
INSTANCE = new HiveDefaultCostModel();
}
return INSTANCE;
}
private HiveDefaultCostModel() {
super(Sets.newHashSet(DefaultJoinAlgorithm.INSTANCE));
}
@Override
public RelOptCost getDefaultCost() {
return HiveCost.FACTORY.makeZeroCost();
}
@Override
public RelOptCost getScanCost(HiveTableScan ts) {
return HiveCost.FACTORY.makeZeroCost();
}
@Override
public RelOptCost getAggregateCost(HiveAggregate aggregate) {
return HiveCost.FACTORY.makeZeroCost();
}
/**
* Default join algorithm. Cost is based on cardinality.
*/
public static class DefaultJoinAlgorithm implements JoinAlgorithm {
public static final JoinAlgorithm INSTANCE = new DefaultJoinAlgorithm();
private static final String ALGORITHM_NAME = "none";
@Override
public String toString() {
return ALGORITHM_NAME;
}
@Override
public boolean isExecutable(HiveJoin join) {
return true;
}
@Override
public RelOptCost getCost(HiveJoin join) {
double leftRCount = RelMetadataQuery.getRowCount(join.getLeft());
double rightRCount = RelMetadataQuery.getRowCount(join.getRight());
return HiveCost.FACTORY.makeCost(leftRCount + rightRCount, 0.0, 0.0);
}
@Override
public ImmutableList getCollation(HiveJoin join) {
return null;
}
@Override
public RelDistribution getDistribution(HiveJoin join) {
return null;
}
@Override
public Double getMemory(HiveJoin join) {
return null;
}
@Override
public Double getCumulativeMemoryWithinPhaseSplit(HiveJoin join) {
return null;
}
@Override
public Boolean isPhaseTransition(HiveJoin join) {
return false;
}
@Override
public Integer getSplitCount(HiveJoin join) {
return null;
}
}
}