org.apache.flink.table.planner.plan.rules.logical.FlinkJoinPushExpressionsRule Maven / Gradle / Ivy

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This module bridges Table/SQL API and runtime. It contains all resources that are required during pre-flight and runtime phase. The content of this module is work-in-progress. It will replace flink-table-planner once it is stable. See FLINK-11439 and FLIP-32 for more details.

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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.flink.table.planner.plan.rules.logical;

import org.apache.calcite.plan.RelOptRule;
import org.apache.calcite.plan.RelOptRuleCall;
import org.apache.calcite.plan.RelOptUtil;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.core.Join;
import org.apache.calcite.rel.core.RelFactories;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.tools.RelBuilder;
import org.apache.calcite.tools.RelBuilderFactory;

/**
 * This rules is copied from Calcite's {@link org.apache.calcite.rel.rules.JoinPushExpressionsRule}.
 * Modification: - Supports SEMI/ANTI join using {@link
 * org.apache.flink.table.planner.plan.utils.FlinkRelOptUtil#pushDownJoinConditions} - Only push
 * down calls on non-time-indicator field.
 */

/**
 * Planner rule that pushes down expressions in "equal" join condition.
 *
 * For example, given "emp JOIN dept ON emp.deptno + 1 = dept.deptno", adds a project above "emp"
 * that computes the expression "emp.deptno + 1". The resulting join condition is a simple
 * combination of AND, equals, and input fields, plus the remaining non-equal conditions.
 */
public class FlinkJoinPushExpressionsRule extends RelOptRule {

    public static final FlinkJoinPushExpressionsRule INSTANCE =
            new FlinkJoinPushExpressionsRule(Join.class, RelFactories.LOGICAL_BUILDER);

    /** Creates a JoinPushExpressionsRule. */
    public FlinkJoinPushExpressionsRule(
            Class clazz, RelBuilderFactory relBuilderFactory) {
        super(operand(clazz, any()), relBuilderFactory, null);
    }

    @Deprecated // to be removed before 2.0
    public FlinkJoinPushExpressionsRule(
            Class clazz, RelFactories.ProjectFactory projectFactory) {
        this(clazz, RelBuilder.proto(projectFactory));
    }

    @Override
    public void onMatch(RelOptRuleCall call) {
        Join join = call.rel(0);

        // Push expression in join condition into Project below Join.
        RelNode newJoin = RelOptUtil.pushDownJoinConditions(join, call.builder());

        // If the join is the same, we bail out
        if (newJoin instanceof Join) {
            final RexNode newCondition = ((Join) newJoin).getCondition();
            if (join.getCondition().equals(newCondition)) {
                return;
            }
        }

        call.transformTo(newJoin);
    }
}

// End FlinkJoinPushExpressionsRule.java