xiedeyantu commented on code in PR #4366: URL: https://github.com/apache/calcite/pull/4366#discussion_r2083650302
########## core/src/main/java/org/apache/calcite/rel/rules/SetOpToFilterRule.java: ########## @@ -0,0 +1,241 @@ +/* + * 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.RelRule; +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rel.core.Filter; +import org.apache.calcite.rel.core.Intersect; +import org.apache.calcite.rel.core.Minus; +import org.apache.calcite.rel.core.SetOp; +import org.apache.calcite.rel.core.Union; +import org.apache.calcite.rex.RexNode; +import org.apache.calcite.rex.RexUtil; +import org.apache.calcite.tools.RelBuilder; +import org.apache.calcite.util.Pair; + +import org.checkerframework.checker.nullness.qual.Nullable; +import org.immutables.value.Value; + +import java.util.ArrayList; +import java.util.LinkedHashMap; +import java.util.List; +import java.util.Map; + +/** + * Rule that replaces {@link SetOp} operator with {@link Filter} + * when both inputs are from the same source with only filter conditions differing. + * For nested filters, the rule {@link CoreRules#FILTER_MERGE} + * should be used prior to invoking this one. + * + * <p>Example: + * + * <p>UNION + * <blockquote><pre> + * SELECT mgr, comm FROM emp WHERE mgr = 12 + * UNION + * SELECT mgr, comm FROM emp WHERE comm = 5 + * + * is rewritten to + * + * SELECT DISTINCT mgr, comm FROM emp + * WHERE mgr = 12 OR comm = 5 + * </pre></blockquote> + * + * <p>INTERSECT + * <blockquote><pre> + * SELECT mgr, comm FROM emp WHERE mgr = 12 + * INTERSECT + * SELECT mgr, comm FROM emp WHERE comm = 5 + * + * is rewritten to + * + * SELECT DISTINCT mgr, comm FROM emp + * WHERE mgr = 12 AND comm = 5 + * </pre></blockquote> + * + * <p>EXCEPT + * <blockquote><pre> + * SELECT mgr, comm FROM emp WHERE mgr = 12 + * EXCEPT + * SELECT mgr, comm FROM emp WHERE comm = 5 + * + * is rewritten to + * + * SELECT DISTINCT mgr, comm FROM emp + * WHERE mgr = 12 AND NOT(comm = 5) + * </pre></blockquote> + */ [email protected] +public class SetOpToFilterRule + extends RelRule<SetOpToFilterRule.Config> + implements TransformationRule { + + /** Creates an SetOpToFilterRule. */ + protected SetOpToFilterRule(Config config) { + super(config); + } + + //~ Methods ---------------------------------------------------------------- + + @Override public void onMatch(RelOptRuleCall call) { + config.matchHandler().accept(this, call); + } + + private void match(RelOptRuleCall call) { + final SetOp setOp = call.rel(0); + final List<RelNode> inputs = setOp.getInputs(); + if (setOp.all || inputs.size() < 2) { + return; + } + + final RelBuilder builder = call.builder(); + Pair<RelNode, RexNode> first = extractSourceAndCond(inputs.get(0).stripped()); + // Map to store conditions grouped by <sourceRelNode, inputPosition>. + // Valid cond positions are set to null and others are tagged with + // input indices for map-based grouping. + Map<Pair<RelNode, Integer>, List<@Nullable RexNode>> sourceToConds = + new LinkedHashMap<>(); + + RelNode firstSource = first.left; + sourceToConds.computeIfAbsent(Pair.of(firstSource, null), + k -> new ArrayList<>()).add(first.right); + + for (int i = 1; i < inputs.size(); i++) { + final RelNode input = inputs.get(i).stripped(); + final Pair<RelNode, @Nullable RexNode> pair = extractSourceAndCond(input); + sourceToConds.computeIfAbsent(Pair.of(pair.left, pair.right != null ? null : i), + k -> new ArrayList<>()).add(pair.right); + } + + if (sourceToConds.size() == inputs.size()) { + return; + } + + int branchCount = 0; + for (Map.Entry<Pair<RelNode, Integer>, List<@Nullable RexNode>> entry + : sourceToConds.entrySet()) { + Pair<RelNode, Integer> left = entry.getKey(); + List<@Nullable RexNode> conds = entry.getValue(); + // If the condition is met (refer to extractSourceAndCond method), + // directly add its corresponding input to the new inputs list. + if (conds.size() == 1 && conds.get(0) == null) { + builder.push(left.left); + branchCount++; + continue; + } + + RexNode combinedCond = + combineConditions(builder, conds, setOp, left.left == firstSource); + + builder.push(left.left) + .filter(combinedCond); + branchCount++; + } + + buildSetOp(builder, branchCount, setOp) Review Comment: Please wait for me to fix the ci error. -- This is an automated message from the Apache Git Service. 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