gortiz commented on code in PR #14296: URL: https://github.com/apache/pinot/pull/14296#discussion_r1818760763
########## pinot-query-planner/src/main/java/org/apache/pinot/query/planner/logical/ParentToChildrenCalculator.java: ########## @@ -0,0 +1,56 @@ +/** + * 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.pinot.query.planner.logical; + +import java.util.Collections; +import java.util.IdentityHashMap; +import java.util.Set; +import org.apache.pinot.query.planner.plannode.MailboxSendNode; +import org.apache.pinot.query.planner.plannode.PlanNodeVisitor; + + +/** + * Utility class to calculate the parent to children mapping for a given plan tree. + */ +public class ParentToChildrenCalculator { + private ParentToChildrenCalculator() { + } + + /** + * Returns an identity map indexed by the parent node, with the value being a set of its <strong>direct</strong> child + * nodes. + */ + public static IdentityHashMap<MailboxSendNode, Set<MailboxSendNode>> calculate(MailboxSendNode root) { + Visitor visitor = new Visitor(); + root.getInputs().forEach(node -> node.visit(visitor, root)); + + return visitor._parentToChild; + } + + private static class Visitor extends PlanNodeVisitor.DepthFirstVisitor<Void, MailboxSendNode> { + private IdentityHashMap<MailboxSendNode, Set<MailboxSendNode>> _parentToChild = new IdentityHashMap<>(); + + @Override + public Void visitMailboxSend(MailboxSendNode node, MailboxSendNode parent) { + _parentToChild.computeIfAbsent(parent, k -> Collections.newSetFromMap(new IdentityHashMap<>())).add(node); Review Comment: just to optimize the lookups assuming we always calls with the same instances. Otherwise we would need to use equals and hashcodes defined in the PlanNode, which is very expensive because it is recursive (they call equals and hashcode in inputs). -- 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...@pinot.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org For additional commands, e-mail: commits-h...@pinot.apache.org
