iwanttobepowerful commented on code in PR #4619: URL: https://github.com/apache/calcite/pull/4619#discussion_r2549396338
########## core/src/main/java/org/apache/calcite/rel/rules/MarkToSemiOrAntiJoinRule.java: ########## @@ -0,0 +1,139 @@ +/* + * 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.Filter; +import org.apache.calcite.rel.core.Join; +import org.apache.calcite.rel.core.JoinRelType; +import org.apache.calcite.rel.core.Project; +import org.apache.calcite.rex.RexCall; +import org.apache.calcite.rex.RexInputRef; +import org.apache.calcite.rex.RexNode; +import org.apache.calcite.sql.SqlKind; +import org.apache.calcite.tools.RelBuilder; +import org.apache.calcite.util.ImmutableBitSet; + +import org.immutables.value.Value; + +import java.util.ArrayList; +import java.util.List; + +import static org.apache.calcite.plan.RelOptUtil.conjunctions; + +/** + * Rule to simplify a mark join to semi join or anti join. + */ [email protected] +public class MarkToSemiOrAntiJoinRule + extends RelRule<MarkToSemiOrAntiJoinRule.Config> + implements TransformationRule { + + + /** Creates a MarkToSemiOrAntiJoinRule. */ + protected MarkToSemiOrAntiJoinRule(Config config) { + super(config); + } + + @Override public void onMatch(RelOptRuleCall call) { + final Project project = call.rel(0); + final Filter filter = call.rel(1); + final Join join = call.rel(2); + final RelBuilder builder = call.builder(); + + int markIndex = join.getRowType().getFieldCount() - 1; + ImmutableBitSet projectColumns = RelOptUtil.InputFinder.bits(project.getProjects(), null); + ImmutableBitSet filterColumns = RelOptUtil.InputFinder.bits(filter.getCondition()); + // Proj <- does not project marker + // Filter <- use marker in condition + // Join <- mark join + if (projectColumns.get(markIndex) || !filterColumns.get(markIndex)) { + return; + } + + // After decompose the filter condition by AND, there are only two cases to simplify: + // 1. only reference the marker, simplify to semi join + // 2. NOT(marker), and the join condition only contains IS [NOT] DISTINCT FROM, + // simplify to anti join + boolean toSemi = false; + boolean toAnti = false; + List<RexNode> filterConditions = RelOptUtil.conjunctions(filter.getCondition()); + List<RexNode> newFilterConditions = new ArrayList<>(); + for (RexNode condition : filterConditions) { + final ImmutableBitSet inputBits = RelOptUtil.InputFinder.bits(condition); + // marker not referenced + if (!inputBits.get(markIndex)) { + newFilterConditions.add(condition); + continue; + } + + // only marker referenced, to semi join + if (condition instanceof RexInputRef && !toAnti) { + toSemi = true; + continue; + } + // NOT(marker), and the join condition only contains IS [NOT] DISTINCT FROM, to anti join + if (condition instanceof RexCall + && condition.isA(SqlKind.NOT) + && ((RexCall) condition).getOperands().get(0) instanceof RexInputRef + && onlyContainsDistinctFrom(join.getCondition()) + && !toSemi) { + toAnti = true; + continue; + } + // other forms cannot be eliminated + return; + } + JoinRelType newJoinType = toSemi ? JoinRelType.SEMI : JoinRelType.ANTI; + RelNode result + = builder.push(join.getLeft()).push(join.getRight()) + .join(newJoinType, join.getCondition()) + .filter(newFilterConditions) + .project(project.getProjects()) + .build(); + call.transformTo(result); + } + + private static boolean onlyContainsDistinctFrom(RexNode condition) { + List<RexNode> conjunctions = conjunctions(condition); + for (RexNode expr : conjunctions) { + if (!expr.isA(SqlKind.IS_DISTINCT_FROM) && !expr.isA(SqlKind.IS_NOT_DISTINCT_FROM)) { + return false; + } + } + return true; + } + + /** Rule configuration. */ + @Value.Immutable + public interface Config extends RelRule.Config { + Config DEFAULT = ImmutableMarkToSemiOrAntiJoinRule.Config.of() + .withOperandSupplier(b1 -> + b1.operand(Project.class).oneInput(b2 -> + b2.operand(Filter.class).oneInput(b3 -> + b3.operand(Join.class).predicate(join -> join.getJoinType() == JoinRelType.MARK) Review Comment: I think there are some scenarios where simplifying a filter + mark join (correlated) into a semi/anti join (correlated) is straightforward. This optimization can be accomplished before entering the decorrelation phase, without the need to defer it to the decorrelation stage itself. Perhaps there are differences in the scope of problems we intend to address by introducing mark joins. My idea is that introducing mark joins can elegantly resolve CALCITE-3373. Perhaps your primary consideration for introducing mark joins is to adopt the decorrelation framework proposed in the paper? I think mark joins are independent of the decorrelation framework described in the paper. -- 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]
