org.apache.drill.exec.planner.physical.SubsetTransformer.java Source code

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Here is the source code for org.apache.drill.exec.planner.physical.SubsetTransformer.java

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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.drill.exec.planner.physical;

import com.google.common.collect.Sets;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.plan.ConventionTraitDef;
import org.apache.calcite.plan.RelOptRule;
import org.apache.calcite.plan.RelOptRuleCall;
import org.apache.calcite.plan.RelTrait;
import org.apache.calcite.plan.RelTraitSet;
import org.apache.calcite.plan.volcano.RelSubset;

import java.util.Set;

public abstract class SubsetTransformer<T extends RelNode, E extends Exception> {
    static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(SubsetTransformer.class);

    public abstract RelNode convertChild(T current, RelNode child) throws E;

    private final RelOptRuleCall call;

    public SubsetTransformer(RelOptRuleCall call) {
        this.call = call;
    }

    public RelTraitSet newTraitSet(RelTrait... traits) {
        RelTraitSet set = call.getPlanner().emptyTraitSet();
        for (RelTrait t : traits) {
            set = set.plus(t);
        }
        return set;

    }

    public boolean go(T n, RelNode candidateSet) throws E {
        if (!(candidateSet instanceof RelSubset)) {
            return false;
        }

        boolean transform = false;
        Set<RelNode> transformedRels = Sets.newIdentityHashSet();
        Set<RelTraitSet> traitSets = Sets.newHashSet();

        //1, get all the target traitsets from candidateSet's rel list,
        for (RelNode rel : ((RelSubset) candidateSet).getRelList()) {
            if (isPhysical(rel)) {
                final RelTraitSet relTraitSet = rel.getTraitSet();
                if (!traitSets.contains(relTraitSet)) {
                    traitSets.add(relTraitSet);
                    logger.trace("{}.convertChild get traitSet {}", this.getClass().getSimpleName(), relTraitSet);
                }
            }
        }

        //2, convert the candidateSet to targeted taitSets
        for (RelTraitSet traitSet : traitSets) {
            RelNode newRel = RelOptRule.convert(candidateSet, traitSet.simplify());
            if (transformedRels.contains(newRel)) {
                continue;
            }
            transformedRels.add(newRel);

            logger.trace("{}.convertChild to convert NODE {} ,AND {}", this.getClass().getSimpleName(), n, newRel);
            RelNode out = convertChild(n, newRel);

            //RelNode out = convertChild(n, rel);
            if (out != null) {
                call.transformTo(out);
                transform = true;
            }
        }

        return transform;
    }

    private boolean isPhysical(RelNode n) {
        return n.getTraitSet().getTrait(ConventionTraitDef.INSTANCE).equals(Prel.DRILL_PHYSICAL);
    }

    private boolean isDefaultDist(RelNode n) {
        return n.getTraitSet().getTrait(DrillDistributionTraitDef.INSTANCE).equals(DrillDistributionTrait.DEFAULT);
    }

}