xiedeyantu commented on code in PR #4280: URL: https://github.com/apache/calcite/pull/4280#discussion_r2034646672
########## core/src/main/java/org/apache/calcite/rel/rules/JoinConditionOrExpansionRule.java: ########## @@ -0,0 +1,299 @@ +/* + * 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.plan.RelOptRuleCall; +import org.apache.calcite.plan.RelOptUtil; +import org.apache.calcite.plan.RelRule; +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rel.core.Join; +import org.apache.calcite.rel.core.JoinRelType; +import org.apache.calcite.rex.RexNode; +import org.apache.calcite.tools.RelBuilder; + +import org.immutables.value.Value; + +import java.util.ArrayList; +import java.util.List; +import java.util.stream.Collectors; + +/** + * Planner rule that matches a + * {@link org.apache.calcite.rel.core.Join} + * and expands OR clauses in join conditions. + * + * <p>this rule would expand the OR condition into + * two separate join conditions, allowing the optimizer + * to handle these conditions more effectively. + */ +@Value.Enclosing +public class JoinConditionOrExpansionRule + extends RelRule<JoinConditionOrExpansionRule.Config> + implements TransformationRule { + + /** Creates an JoinConditionExpansionOrRule. */ + protected JoinConditionOrExpansionRule(Config config) { + super(config); + } + + //~ Methods ---------------------------------------------------------------- + + @Override public void onMatch(RelOptRuleCall call) { + Join join = call.rel(0); + RelBuilder relBuilder = call.builder(); + List<RexNode> orConds = RelOptUtil.disjunctions(join.getCondition()); + + if (orConds.size() <= 1) { + return; + } + + RelNode converted; + switch (join.getJoinType()) { + case INNER: + converted = expandInnerJoin(join, orConds, relBuilder); + break; + case SEMI: + converted = + expandSemiOrAntiJoin(join, JoinRelType.SEMI, orConds, relBuilder); + break; + case ANTI: + converted = + expandSemiOrAntiJoin(join, JoinRelType.ANTI, orConds, relBuilder); + break; + case LEFT: + converted = expandLeftJoin(join, orConds, relBuilder); + break; + case RIGHT: + converted = expandRightJoin(join, orConds, relBuilder); + break; + case FULL: + converted = expandFullJoin(join, orConds, relBuilder); + break; + default: + return; + } + call.transformTo(converted); + } + + /** + * This method will make the following conversions. + * + * <p>Project[*] + * └── Join[OR(t1.id=t2.id, t1.age=t2.age), left] + * ├── TableScan[t1] + * └── TableScan[t2] + * + * <p>into + * + * <p>Project[*] + * └── UnionAll + * ├── Join[t1.id=t2.id, inner] + * │ ├── TableScan[t1] + * │ └── TableScan[t2] + * ├── Join[t1.age=t2.age AND t1.id≠t2.id, inner] + * │ ├── TableScan[t1] + * │ └── TableScan[t2] + * └── Project[t1-side cols + NULLs] + * └── Join[t1.id=t2.id, anti] + * ├── Join[t1.age=t2.age, anti] + * │ ├── TableScan[t1] + * │ └── TableScan[t2] + * └── TableScan[t2] + */ + private RelNode expandLeftJoin(Join join, List<RexNode> orConds, + RelBuilder relBuilder) { + List<RelNode> joins = expandLeftJoinToRelNodes(join, orConds, relBuilder); + return relBuilder.pushAll(joins) + .union(true, joins.size()) + .build(); + } + + private List<RelNode> expandLeftJoinToRelNodes(Join join, List<RexNode> orConds, + RelBuilder relBuilder) { + List<RelNode> joins = new ArrayList<>(); + joins.addAll(expandInnerJoinToRelNodes(join, orConds, relBuilder)); + joins.add(expandSemiOrAntiJoin(join, JoinRelType.ANTI, orConds, relBuilder)); + return joins; + } + + private RelNode expandRightJoin(Join join, List<RexNode> orConds, + RelBuilder relBuilder) { + List<RelNode> joins = expandRightJoinToRelNodes(join, orConds, relBuilder); + return relBuilder.pushAll(joins) + .union(true, joins.size()) + .build(); + } + + private List<RelNode> expandRightJoinToRelNodes(Join join, List<RexNode> orConds, Review Comment: Thanks! There is indeed a problem here. My idea is that `RIGHT JOIN` does not support direct `OR` expansion for the time being, and it can be converted to `LEFT JOIN` through `JOIN_COMMUTE_OUTER` and then `OR` expansion, which can avoid repeated `JOIN` commute in `JOIN_CONDITION_OR_EXPANSION_RULE` and some complex adaptation. WDYT? -- 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: commits-unsubscr...@calcite.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
