org.apache.hadoop.hive.ql.optimizer.calcite.cost.HiveCostModel Maven / Gradle / Ivy
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* 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 java.util.Set;
import org.apache.calcite.plan.RelOptCost;
import org.apache.calcite.plan.RelOptUtil;
import org.apache.calcite.rel.RelCollation;
import org.apache.calcite.rel.RelDistribution;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
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;
/**
* Cost model interface.
*/
public abstract class HiveCostModel {
private static final Log LOG = LogFactory.getLog(HiveCostModel.class);
private final Set joinAlgorithms;
public HiveCostModel(Set joinAlgorithms) {
this.joinAlgorithms = joinAlgorithms;
}
public abstract RelOptCost getDefaultCost();
public abstract RelOptCost getAggregateCost(HiveAggregate aggregate);
public abstract RelOptCost getScanCost(HiveTableScan ts);
public RelOptCost getJoinCost(HiveJoin join) {
// Select algorithm with min cost
JoinAlgorithm joinAlgorithm = null;
RelOptCost minJoinCost = null;
if (LOG.isDebugEnabled()) {
LOG.debug("Join algorithm selection for:\n" + RelOptUtil.toString(join));
}
for (JoinAlgorithm possibleAlgorithm : this.joinAlgorithms) {
if (!possibleAlgorithm.isExecutable(join)) {
continue;
}
RelOptCost joinCost = possibleAlgorithm.getCost(join);
if (LOG.isDebugEnabled()) {
LOG.debug(possibleAlgorithm + " cost: " + joinCost);
}
if (minJoinCost == null || joinCost.isLt(minJoinCost) ) {
joinAlgorithm = possibleAlgorithm;
minJoinCost = joinCost;
}
}
if (LOG.isDebugEnabled()) {
LOG.debug(joinAlgorithm + " selected");
}
join.setJoinAlgorithm(joinAlgorithm);
join.setJoinCost(minJoinCost);
return minJoinCost;
}
/**
* Interface for join algorithm.
*/
public interface JoinAlgorithm {
public String toString();
public boolean isExecutable(HiveJoin join);
public RelOptCost getCost(HiveJoin join);
public ImmutableList getCollation(HiveJoin join);
public RelDistribution getDistribution(HiveJoin join);
public Double getMemory(HiveJoin join);
public Double getCumulativeMemoryWithinPhaseSplit(HiveJoin join);
public Boolean isPhaseTransition(HiveJoin join);
public Integer getSplitCount(HiveJoin join);
}
}