com.hazelcast.org.apache.calcite.rel.rules.JoinUnionTransposeRule 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 com.hazelcast.org.apache.calcite.rel.rules;

import com.hazelcast.org.apache.calcite.plan.RelOptRuleCall;
import com.hazelcast.org.apache.calcite.plan.RelOptRuleOperand;
import com.hazelcast.org.apache.calcite.plan.RelRule;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.core.Join;
import com.hazelcast.org.apache.calcite.rel.core.SetOp;
import com.hazelcast.org.apache.calcite.rel.core.Union;
import com.hazelcast.org.apache.calcite.tools.RelBuilderFactory;

import org.immutables.value.Value;

import java.util.ArrayList;
import java.util.List;

/**
 * Planner rule that pushes a
 * {@link com.hazelcast.org.apache.calcite.rel.core.Join}
 * past a non-distinct {@link com.hazelcast.org.apache.calcite.rel.core.Union}.
 *
 * @see CoreRules#JOIN_LEFT_UNION_TRANSPOSE
 * @see CoreRules#JOIN_RIGHT_UNION_TRANSPOSE
 */
@Value.Enclosing
public class JoinUnionTransposeRule
    extends RelRule
    implements TransformationRule {

  /** Creates a JoinUnionTransposeRule. */
  protected JoinUnionTransposeRule(Config config) {
    super(config);
  }

  @Deprecated // to be removed before 2.0
  public JoinUnionTransposeRule(RelOptRuleOperand operand,
      RelBuilderFactory relBuilderFactory, String description) {
    this(Config.LEFT.withRelBuilderFactory(relBuilderFactory)
        .withDescription(description)
        .withOperandSupplier(b -> b.exactly(operand))
        .as(Config.class));
  }

  @Override public void onMatch(RelOptRuleCall call) {
    final Join join = call.rel(0);
    final Union unionRel;
    RelNode otherInput;
    boolean unionOnLeft;
    if (call.rel(1) instanceof Union) {
      unionRel = call.rel(1);
      otherInput = call.rel(2);
      unionOnLeft = true;
    } else {
      otherInput = call.rel(1);
      unionRel = call.rel(2);
      unionOnLeft = false;
    }
    if (!unionRel.all) {
      return;
    }
    if (!join.getVariablesSet().isEmpty()) {
      return;
    }
    // The UNION ALL cannot be on the null generating side
    // of an outer join (otherwise we might generate incorrect
    // rows for the other side for join keys which lack a match
    // in one or both branches of the union)
    if (unionOnLeft) {
      if (join.getJoinType().generatesNullsOnLeft()) {
        return;
      }
    } else {
      if (join.getJoinType().generatesNullsOnRight()
          || !join.getJoinType().projectsRight()) {
        return;
      }
    }
    List newUnionInputs = new ArrayList<>();
    for (RelNode input : unionRel.getInputs()) {
      RelNode joinLeft;
      RelNode joinRight;
      if (unionOnLeft) {
        joinLeft = input;
        joinRight = otherInput;
      } else {
        joinLeft = otherInput;
        joinRight = input;
      }
      newUnionInputs.add(
          join.copy(
              join.getTraitSet(),
              join.getCondition(),
              joinLeft,
              joinRight,
              join.getJoinType(),
              join.isSemiJoinDone()));
    }
    final SetOp newUnionRel =
        unionRel.copy(unionRel.getTraitSet(), newUnionInputs, true);
    call.transformTo(newUnionRel);
  }

  /** Rule configuration. */
  @Value.Immutable
  public interface Config extends RelRule.Config {
    Config LEFT = ImmutableJoinUnionTransposeRule.Config.of()
        .withDescription("JoinUnionTransposeRule(Union-Other)")
        .withOperandFor(Join.class, Union.class, true);

    Config RIGHT = ImmutableJoinUnionTransposeRule.Config.of()
        .withDescription("JoinUnionTransposeRule(Other-Union)")
        .withOperandFor(Join.class, Union.class, false);

    @Override default JoinUnionTransposeRule toRule() {
      return new JoinUnionTransposeRule(this);
    }

    /** Defines an operand tree for the given classes. */
    default Config withOperandFor(Class joinClass,
        Class unionClass, boolean left) {
      final Class leftClass =
          left ? unionClass : RelNode.class;
      final Class rightClass =
          left ? RelNode.class : unionClass;
      return withOperandSupplier(b0 ->
          b0.operand(joinClass).inputs(
              b1 -> b1.operand(leftClass).anyInputs(),
              b2 -> b2.operand(rightClass).anyInputs()))
          .as(Config.class);
    }
  }
}