mihaibudiu commented on code in PR #4392: URL: https://github.com/apache/calcite/pull/4392#discussion_r2112399382
########## core/src/main/java/org/apache/calcite/rel/rules/ConflictDetectionHelper.java: ########## @@ -0,0 +1,216 @@ +/* + * 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.rules; + +import org.apache.calcite.rel.core.JoinRelType; + +import com.google.common.collect.ImmutableMap; + +import java.util.HashMap; +import java.util.List; +import java.util.Map; + +/** + * Conflict detection algorithm based on CD-C. More details are in paper: + * <a href="https://15721.courses.cs.cmu.edu/spring2019/papers/23-optimizer2/p493-moerkotte.pdf";> + * On the correct and complete enumeration of the core search space</a>. + */ +public class ConflictDetectionHelper { + + private ConflictDetectionHelper() { + } + + private static final ImmutableMap<JoinRelType, Integer> INDEX_OF_TABLE = + ImmutableMap.<JoinRelType, Integer>builder() + .put(JoinRelType.INNER, 0).put(JoinRelType.SEMI, 1).put(JoinRelType.ANTI, 2) + .put(JoinRelType.LEFT, 3).put(JoinRelType.FULL, 4).build(); + + // TODO: when special attribute is null rejecting, left/full join is + // associative/left_asscom/right_asscom. See table2/3 in paper + private static final boolean[][] ASSOCIATIVE_TABLE = { + // inner-B semi-B anti-B left-B full-B + /* inner-A */ {true, true, true, true, false}, + /* semi-A */ {false, false, false, false, false}, + /* anti-A */ {false, false, false, false, false}, + /* left-A */ {false, false, false, false, false}, + /* full-A */ {false, false, false, false, false}}; + + private static final boolean[][] LEFT_ASSCOM_TABLE = { + // inner-B semi-B anti-B left-B full-B + /* inner-A */ {true, true, true, true, false}, + /* semi-A */ {true, true, true, true, false}, + /* anti-A */ {true, true, true, true, false}, + /* left-A */ {true, true, true, true, false}, + /* full-A */ {false, false, false, false, false}}; + + private static final boolean[][] RIGHT_ASSCOM_TABLE = { + // inner-B semi-B anti-B left-B full-B + /* inner-A */ {true, false, false, false, false}, + /* semi-A */ {false, false, false, false, false}, + /* anti-A */ {false, false, false, false, false}, + /* left-A */ {false, false, false, false, false}, + /* full-A */ {false, false, false, false, false}}; + + /** + * Make conflict rules for join operator based on CD-C. + * + * @param leftSubEdges left sub operators + * @param rightSubEdges right sub operators + * @param joinType current join operator + * @return a map from table set1 to table set2 that if set1 and the tables in the current join + * operator have an intersection, then set2 must be included in the current join operator + */ + public static Map<Long, Long> makeConflictRules( + List<HyperEdge> leftSubEdges, + List<HyperEdge> rightSubEdges, + JoinRelType joinType) { + Map<Long, Long> conflictRules = new HashMap<>(); Review Comment: My experience is that abstractions help code maintenance in the long run. Everyone who needs to read this code will wonder what these long values are, but if they are in a class with a good name, that also documents the fields, it will be clear. This will also distinguish Maps<Long, Long> that represent conflict maps from other Maps with the same type signature that appear in the code. And if you need more methods, you will discover that there is a place to add them, instead of having lots of static methods. -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
