XieJiann commented on code in PR #30774: URL: https://github.com/apache/doris/pull/30774#discussion_r1479207444
########## fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/EliminateGroupByKey.java: ########## @@ -0,0 +1,217 @@ +// 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.doris.nereids.rules.rewrite; + +import org.apache.doris.nereids.properties.FdItem; +import org.apache.doris.nereids.rules.Rule; +import org.apache.doris.nereids.rules.RuleType; +import org.apache.doris.nereids.trees.expressions.Expression; +import org.apache.doris.nereids.trees.expressions.NamedExpression; +import org.apache.doris.nereids.trees.expressions.SlotReference; +import org.apache.doris.nereids.trees.plans.logical.LogicalAggregate; +import org.apache.doris.nereids.trees.plans.logical.LogicalPlan; +import org.apache.doris.qe.ConnectContext; + +import com.google.common.collect.ImmutableSet; + +import java.util.ArrayList; +import java.util.HashSet; +import java.util.List; +import java.util.Set; +import java.util.stream.Collectors; + +/** + * Eliminate group by key based on fd item information. + */ +public class EliminateGroupByKey extends OneRewriteRuleFactory { + @Override + public Rule build() { + return logicalAggregate(logicalProject()).then(agg -> { + Set<Integer> enableNereidsRules = ConnectContext.get().getSessionVariable().getEnableNereidsRules(); + if (!enableNereidsRules.contains(RuleType.ELIMINATE_GROUP_BY_KEY.type())) { + return null; + } + LogicalPlan childPlan = agg.child(); + List<FdItem> uniqueFdItems = new ArrayList<>(); + List<FdItem> nonUniqueFdItems = new ArrayList<>(); + if (agg.getGroupByExpressions().isEmpty() + || agg.getGroupByExpressions().equals(agg.getOutputExpressions()) + || !agg.getGroupByExpressions().stream().allMatch(e -> e instanceof SlotReference) + || agg.getGroupByExpressions().stream().allMatch(e -> + ((SlotReference) e).getColumn().isPresent() && ((SlotReference) e).getTable().isPresent())) { + return null; + } + ImmutableSet<FdItem> fdItems = childPlan.getLogicalProperties().getFunctionalDependencies().getFdItems(); + if (fdItems.isEmpty()) { + return null; + } + List<SlotReference> candiExprs = agg.getGroupByExpressions().stream() + .map(SlotReference.class::cast).collect(Collectors.toList()); + + fdItems.stream().filter(e -> !e.isCandidate()).forEach(e -> { + if (e.isUnique()) { + uniqueFdItems.add(e); + } else { + nonUniqueFdItems.add(e); + } + } + ); + + int minParentExprCnt = -1; + ImmutableSet<SlotReference> minParentExprs = ImmutableSet.of(); + // if unique fd items exists, try to find the one which has the + // smallest parent exprs + for (int i = 0; i < uniqueFdItems.size(); i++) { + FdItem fdItem = uniqueFdItems.get(i); + ImmutableSet<SlotReference> parentExprs = fdItem.getParentExprs(); + if (minParentExprCnt == -1 || parentExprs.size() < minParentExprCnt) { + boolean isContain = isExprsContainFdParent(candiExprs, fdItem); + if (isContain) { + minParentExprCnt = parentExprs.size(); + minParentExprs = ImmutableSet.copyOf(parentExprs); + } + } + } + + Set<Integer> rootExprsSet = new HashSet<>(); + List<SlotReference> rootExprs = new ArrayList<>(); + Set<Integer> eliminateSet = new HashSet<>(); + if (minParentExprs.size() > 0) { + // if any unique fd item found, find the expr which matching parentExprs + // from candiExprs directly + for (int i = 0; i < minParentExprs.size(); i++) { + int index = findEqualExpr(candiExprs, minParentExprs.asList().get(i)); + if (index != -1) { + rootExprsSet.add(new Integer(index)); + } else { + return null; + } + } + } else { + // no unique fd item found, try to find the smallest root exprs set + // from non-unique fd items. + for (int i = 0; i < nonUniqueFdItems.size() && eliminateSet.size() < candiExprs.size(); i++) { + FdItem fdItem = nonUniqueFdItems.get(i); + ImmutableSet<SlotReference> parentExprs = fdItem.getParentExprs(); + boolean isContains = isExprsContainFdParent(candiExprs, fdItem); + if (isContains) { + List<SlotReference> leftDomain = new ArrayList<>(); + List<SlotReference> rightDomain = new ArrayList<>(); + // generate new root exprs + for (int j = 0; j < rootExprs.size(); j++) { + leftDomain.add(rootExprs.get(j)); + boolean isInChild = fdItem.checkExprInChild(rootExprs.get(j), childPlan); + if (!isInChild) { + rightDomain.add(rootExprs.get(j)); + } + } + for (int j = 0; j < parentExprs.size(); j++) { + int index = findEqualExpr(candiExprs, parentExprs.asList().get(j)); + if (index != -1) { + rightDomain.add(candiExprs.get(index)); + if (!eliminateSet.contains(index)) { + leftDomain.add(candiExprs.get(index)); + } + } + } + // check fd can eliminate new candi expr + for (int j = 0; j < candiExprs.size(); j++) { + if (!eliminateSet.contains(j)) { + boolean isInChild = fdItem.checkExprInChild(candiExprs.get(j), childPlan); + if (isInChild) { + eliminateSet.add(j); + } + } + } + // if fd eliminate new candi exprs or new root exprs is smaller than the older, + // than use new root expr to replace old ones + List<SlotReference> newRootExprs = leftDomain.size() <= rightDomain.size() + ? leftDomain : rightDomain; + rootExprs.clear(); + rootExprs.addAll(newRootExprs); + } + } + } + // find the root expr, add into root exprs set, indicate the index in + // candiExprs list + for (int i = 0; i < rootExprs.size(); i++) { + int index = findEqualExpr(candiExprs, rootExprs.get(i)); + if (index != -1) { + rootExprsSet.add(new Integer(index)); + } else { + return null; + } + } Review Comment: We don't need it after checking isContaining -- This is an automated message from the Apache Git Service. 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