modules/sql-engine/src/main/java/org/apache/ignite/internal/sql/engine/rule/HashJoinConverterRule.java

/*
 * 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.ignite.internal.sql.engine.rule;

import static org.apache.ignite.internal.util.CollectionUtils.nullOrEmpty;

import org.apache.calcite.plan.RelOptCluster;
import org.apache.calcite.plan.RelOptPlanner;
import org.apache.calcite.plan.RelOptRule;
import org.apache.calcite.plan.RelOptRuleCall;
import org.apache.calcite.plan.RelTraitSet;
import org.apache.calcite.rel.PhysicalNode;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.logical.LogicalJoin;
import org.apache.calcite.rel.metadata.RelMetadataQuery;
import org.apache.calcite.rex.RexCall;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.rex.RexVisitor;
import org.apache.calcite.rex.RexVisitorImpl;
import org.apache.calcite.sql.SqlKind;
import org.apache.calcite.util.Util;
import org.apache.ignite.internal.sql.engine.rel.IgniteConvention;
import org.apache.ignite.internal.sql.engine.rel.IgniteHashJoin;

/**
 * Hash join converter.
 */
public class HashJoinConverterRule extends AbstractIgniteConverterRule<LogicalJoin> {
    public static final RelOptRule INSTANCE = new HashJoinConverterRule();

    /**
     * Creates a converter.
     */
    public HashJoinConverterRule() {
        super(LogicalJoin.class, "HashJoinConverter");
    }

    /** {@inheritDoc} */
    @Override
    public boolean matches(RelOptRuleCall call) {
        LogicalJoin logicalJoin = call.rel(0);

        return !nullOrEmpty(logicalJoin.analyzeCondition().pairs())
                && logicalJoin.analyzeCondition().isEqui() && acceptableConditions(logicalJoin.getCondition());
    }

    private static boolean acceptableConditions(RexNode node) {
        RexVisitor<Void> v = new RexVisitorImpl<>(true) {
            @Override
            public Void visitCall(RexCall call) {
                SqlKind opKind = call.getOperator().getKind();
                if (opKind != SqlKind.EQUALS && opKind != SqlKind.AND) {
                    throw Util.FoundOne.NULL;
                }
                return super.visitCall(call);
            }
        };

        try {
            node.accept(v);

            return true;
        } catch (Util.FoundOne e) {
            return false;
        }
    }

    /** {@inheritDoc} */
    @Override
    protected PhysicalNode convert(RelOptPlanner planner, RelMetadataQuery mq, LogicalJoin rel) {
        RelOptCluster cluster = rel.getCluster();
        RelTraitSet outTraits = cluster.traitSetOf(IgniteConvention.INSTANCE);
        RelTraitSet leftInTraits = cluster.traitSetOf(IgniteConvention.INSTANCE);
        RelTraitSet rightInTraits = cluster.traitSetOf(IgniteConvention.INSTANCE);
        RelNode left = convert(rel.getLeft(), leftInTraits);
        RelNode right = convert(rel.getRight(), rightInTraits);

        return new IgniteHashJoin(cluster, outTraits, left, right, rel.getCondition(), rel.getVariablesSet(), rel.getJoinType());
    }
}