/**
* 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.physical;
import java.io.IOException;
import java.util.List;
import org.apache.drill.common.expression.FieldReference;
import org.apache.drill.common.logical.data.JoinCondition;
import org.apache.drill.exec.physical.base.PhysicalOperator;
import org.apache.drill.exec.physical.config.MergeJoinPOP;
import org.apache.drill.exec.planner.cost.DrillCostBase;
import org.apache.drill.exec.planner.cost.DrillCostBase.DrillCostFactory;
import org.apache.drill.exec.record.BatchSchema.SelectionVectorMode;
import org.eigenbase.rel.InvalidRelException;
import org.eigenbase.rel.JoinRelBase;
import org.eigenbase.rel.JoinRelType;
import org.eigenbase.rel.RelNode;
import org.eigenbase.rel.metadata.RelMetadataQuery;
import org.eigenbase.relopt.RelOptCluster;
import org.eigenbase.relopt.RelOptCost;
import org.eigenbase.relopt.RelOptPlanner;
import org.eigenbase.relopt.RelOptUtil;
import org.eigenbase.relopt.RelTraitSet;
import org.eigenbase.rex.RexNode;
import org.eigenbase.util.Pair;
import com.google.common.collect.Lists;
public class MergeJoinPrel extends JoinPrel {
/** Creates a MergeJoiPrel. */
public MergeJoinPrel(RelOptCluster cluster, RelTraitSet traits, RelNode left, RelNode right, RexNode condition,
JoinRelType joinType) throws InvalidRelException {
super(cluster, traits, left, right, condition, joinType);
if (condition.isAlwaysTrue()) {
throw new InvalidRelException("MergeJoinPrel does not support cartesian product join");
}
RexNode remaining = RelOptUtil.splitJoinCondition(left, right, condition, leftKeys, rightKeys);
if (!remaining.isAlwaysTrue() && (leftKeys.size() == 0 || rightKeys.size() == 0)) {
throw new InvalidRelException("MergeJoinPrel only supports equi-join");
}
}
@Override
public JoinRelBase copy(RelTraitSet traitSet, RexNode conditionExpr, RelNode left, RelNode right, JoinRelType joinType, boolean semiJoinDone) {
try {
return new MergeJoinPrel(this.getCluster(), traitSet, left, right, conditionExpr, joinType);
}catch (InvalidRelException e) {
throw new AssertionError(e);
}
}
@Override
public RelOptCost computeSelfCost(RelOptPlanner planner) {
if(PrelUtil.getSettings(getCluster()).useDefaultCosting()) {
return super.computeSelfCost(planner).multiplyBy(.1);
}
double leftRowCount = RelMetadataQuery.getRowCount(this.getLeft());
double rightRowCount = RelMetadataQuery.getRowCount(this.getRight());
// cost of evaluating each leftkey=rightkey join condition
double joinConditionCost = DrillCostBase.COMPARE_CPU_COST * this.getLeftKeys().size();
double cpuCost = joinConditionCost * (leftRowCount + rightRowCount);
DrillCostFactory costFactory = (DrillCostFactory)planner.getCostFactory();
return costFactory.makeCost(leftRowCount + rightRowCount, cpuCost, 0, 0);
}
@Override
public PhysicalOperator getPhysicalOperator(PhysicalPlanCreator creator) throws IOException {
final List<String> fields = getRowType().getFieldNames();
assert isUnique(fields);
final int leftCount = left.getRowType().getFieldCount();
final List<String> leftFields = fields.subList(0, leftCount);
final List<String> rightFields = fields.subList(leftCount, fields.size());
PhysicalOperator leftPop = ((Prel)left).getPhysicalOperator(creator);
PhysicalOperator rightPop = ((Prel)right).getPhysicalOperator(creator);
JoinRelType jtype = this.getJoinType();
List<JoinCondition> conditions = Lists.newArrayList();
for (Pair<Integer, Integer> pair : Pair.zip(leftKeys, rightKeys)) {
conditions.add(new JoinCondition("==", new FieldReference(leftFields.get(pair.left)), new FieldReference(rightFields.get(pair.right))));
}
MergeJoinPOP mjoin = new MergeJoinPOP(leftPop, rightPop, conditions, jtype);
return creator.addMetadata(this, mjoin);
}
@Override
public SelectionVectorMode[] getSupportedEncodings() {
return SelectionVectorMode.NONE_AND_TWO;
}
@Override
public SelectionVectorMode getEncoding() {
return SelectionVectorMode.NONE;
}
}