rubenada commented on a change in pull request #2329: URL: https://github.com/apache/calcite/pull/2329#discussion_r561015434
########## File path: core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableMergeUnion.java ########## @@ -0,0 +1,128 @@ +/* + * 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.adapter.enumerable; + +import org.apache.calcite.linq4j.Ord; +import org.apache.calcite.linq4j.tree.BlockBuilder; +import org.apache.calcite.linq4j.tree.Expression; +import org.apache.calcite.linq4j.tree.Expressions; +import org.apache.calcite.linq4j.tree.ParameterExpression; +import org.apache.calcite.plan.RelOptCluster; +import org.apache.calcite.plan.RelOptCost; +import org.apache.calcite.plan.RelOptPlanner; +import org.apache.calcite.plan.RelTraitSet; +import org.apache.calcite.rel.RelCollation; +import org.apache.calcite.rel.RelCollationTraitDef; +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rel.metadata.RelMetadataQuery; +import org.apache.calcite.util.BuiltInMethod; +import org.apache.calcite.util.Pair; +import org.apache.calcite.util.Util; + +import org.checkerframework.checker.nullness.qual.Nullable; + +import java.util.ArrayList; +import java.util.List; + +/** Implementation of {@link org.apache.calcite.rel.core.Union} in + * {@link org.apache.calcite.adapter.enumerable.EnumerableConvention enumerable calling convention}. + * Performs a union (or union all) of all its inputs (which must be already sorted), + * respecting the order. */ +public class EnumerableMergeUnion extends EnumerableUnion { + + protected EnumerableMergeUnion(RelOptCluster cluster, RelTraitSet traitSet, List<RelNode> inputs, + boolean all) { + super(cluster, traitSet, inputs, all); + final List<RelCollation> collations = traitSet.getTraits(RelCollationTraitDef.INSTANCE); + if (collations == null || collations.isEmpty()) { + throw new IllegalArgumentException("EnumerableMergeUnion with no collation"); + } + } + + public static EnumerableMergeUnion create(RelCollation collation, List<RelNode> inputs, + boolean all) { + final RelOptCluster cluster = inputs.get(0).getCluster(); + final RelTraitSet traitSet = cluster.traitSetOf(EnumerableConvention.INSTANCE).replace( + collation); + return new EnumerableMergeUnion(cluster, traitSet, inputs, all); + } + + @Override public @Nullable RelOptCost computeSelfCost(RelOptPlanner planner, + RelMetadataQuery mq) { + // EnumerableUnion computes the whole union result in memory, whereas EnumerableMergeUnion + // does it step by step, loading only 1 item per input at a time, reflect this optimization + // on the cpu cost: + final RelOptCost cost = super.computeSelfCost(planner, mq); + if (cost == null) { + return null; + } + return planner.getCostFactory().makeCost(cost.getRows(), cost.getCpu() / 2, cost.getIo()); Review comment: Ok, I'll remove this overridden method. Let EnumerableMergeUnion have by default the same cost as EnumerableUnion. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
