com.hazelcast.org.apache.calcite.rel.rules.SemiJoinRemoveRule Maven / Gradle / Ivy
/*
* 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.RelOptRule;
import com.hazelcast.org.apache.calcite.plan.RelOptRuleCall;
import com.hazelcast.org.apache.calcite.rel.core.Join;
import com.hazelcast.org.apache.calcite.rel.core.RelFactories;
import com.hazelcast.org.apache.calcite.rel.logical.LogicalJoin;
import com.hazelcast.org.apache.calcite.tools.RelBuilderFactory;
/**
* Planner rule that removes a {@code SemiJoin}s from a join tree.
*
* It is invoked after attempts have been made to convert a SemiJoin to an
* indexed scan on a join factor have failed. Namely, if the join factor does
* not reduce to a single table that can be scanned using an index.
*
*
It should only be enabled if all SemiJoins in the plan are advisory; that
* is, they can be safely dropped without affecting the semantics of the query.
*/
public class SemiJoinRemoveRule extends RelOptRule implements TransformationRule {
public static final SemiJoinRemoveRule INSTANCE =
new SemiJoinRemoveRule(RelFactories.LOGICAL_BUILDER);
//~ Constructors -----------------------------------------------------------
/** Creates a SemiJoinRemoveRule. */
public SemiJoinRemoveRule(RelBuilderFactory relBuilderFactory) {
super(operandJ(LogicalJoin.class, null, Join::isSemiJoin, any()),
relBuilderFactory, null);
}
//~ Methods ----------------------------------------------------------------
public void onMatch(RelOptRuleCall call) {
call.transformTo(call.rel(0).getInput(0));
}
}