/*
* 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.eigenbase.rel.rules;
import java.util.BitSet;
import java.util.List;
import org.eigenbase.rel.AggregateRelBase;
import org.eigenbase.rel.JoinInfo;
import org.eigenbase.rel.JoinRelBase;
import org.eigenbase.rel.ProjectRelBase;
import org.eigenbase.rel.RelNode;
import org.eigenbase.relopt.Convention;
import org.eigenbase.relopt.RelOptRule;
import org.eigenbase.relopt.RelOptRuleCall;
import org.eigenbase.relopt.RelOptUtil;
import org.eigenbase.util.ImmutableIntList;
import org.eigenbase.util.IntList;
import net.hydromatic.optiq.util.BitSets;
import com.google.common.collect.Lists;
/**
* Planner rule that creates a {@code SemiJoinRule} from a
* {@link org.eigenbase.rel.JoinRelBase} on top of a
* {@link org.eigenbase.rel.AggregateRel}.
*/
public class SemiJoinRule extends RelOptRule {
public static final SemiJoinRule INSTANCE = new SemiJoinRule();
private SemiJoinRule() {
super(
operand(ProjectRelBase.class,
some(operand(JoinRelBase.class,
some(operand(RelNode.class, any()),
operand(AggregateRelBase.class, any()))))));
}
@Override
public void onMatch(RelOptRuleCall call) {
final ProjectRelBase project = call.rel(0);
final JoinRelBase join = call.rel(1);
final RelNode left = call.rel(2);
final AggregateRelBase aggregate = call.rel(3);
final BitSet bits = RelOptUtil.InputFinder.bits(project.getProjects(),
null);
final BitSet rightBits = BitSets.range(left.getRowType().getFieldCount(),
join.getRowType().getFieldCount());
if (bits.intersects(rightBits)) {
return;
}
final JoinInfo joinInfo = join.analyzeCondition();
if (!joinInfo.rightSet().equals(BitSets.range(aggregate.getGroupCount()))) {
// Rule requires that aggregate key to be the same as the join key.
// By the way, neither a super-set nor a sub-set would work.
return;
}
final List<Integer> newRightKeys = Lists.newArrayList();
final IntList aggregateKeys = BitSets.toList(aggregate.getGroupSet());
for (int key : joinInfo.rightKeys) {
newRightKeys.add(aggregateKeys.get(key));
}
final SemiJoinRel semiJoin =
new SemiJoinRel(join.getCluster(),
join.getCluster().traitSetOf(Convention.NONE),
left, aggregate.getChild(),
join.getCondition(), joinInfo.leftKeys,
ImmutableIntList.copyOf(newRightKeys));
final ProjectRelBase newProject =
project.copy(project.getTraitSet(), semiJoin, project.getProjects(),
project.getRowType());
call.transformTo(RemoveTrivialProjectRule.strip(newProject));
}
}
// End SemiJoinRule.java