/* * 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.calcite.rel; import org.apache.calcite.plan.RelOptPlanner; import org.apache.calcite.plan.RelTraitDef; import org.apache.calcite.plan.RelTraitSet; import org.apache.calcite.rel.core.Exchange; import org.apache.calcite.rel.logical.LogicalExchange; /** * Definition of the distribution trait. * * <p>Distribution is a physical property (i.e. a trait) because it can be * changed without loss of information. The converter to do this is the * {@link Exchange} operator. */ public class RelDistributionTraitDef extends RelTraitDef<RelDistribution> { public static final RelDistributionTraitDef INSTANCE = new RelDistributionTraitDef(); private RelDistributionTraitDef() { } public Class<RelDistribution> getTraitClass() { return RelDistribution.class; } public String getSimpleName() { return "dist"; } public RelDistribution getDefault() { return RelDistributions.ANY; } public RelNode convert(RelOptPlanner planner, RelNode rel, RelDistribution toDistribution, boolean allowInfiniteCostConverters) { if (toDistribution == RelDistributions.ANY) { return rel; } // Create a logical sort, then ask the planner to convert its remaining // traits (e.g. convert it to an EnumerableSortRel if rel is enumerable // convention) final Exchange exchange = LogicalExchange.create(rel, toDistribution); RelNode newRel = planner.register(exchange, rel); final RelTraitSet newTraitSet = rel.getTraitSet().replace(toDistribution); if (!newRel.getTraitSet().equals(newTraitSet)) { newRel = planner.changeTraits(newRel, newTraitSet); } return newRel; } public boolean canConvert(RelOptPlanner planner, RelDistribution fromTrait, RelDistribution toTrait) { return true; } }