mcvsubbu commented on a change in pull request #4323: [Controller Separation] Add logic for lead controller resource URL: https://github.com/apache/incubator-pinot/pull/4323#discussion_r304999654
########## File path: pinot-common/src/main/java/org/apache/pinot/common/utils/helix/LeadControllerUtils.java ########## @@ -0,0 +1,97 @@ +/** + * 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.common.utils.helix; + +import java.util.Map; +import java.util.Set; +import org.apache.helix.model.ExternalView; +import org.apache.helix.model.MasterSlaveSMD; +import org.apache.pinot.common.utils.HashUtils; +import org.apache.pinot.common.utils.StringUtil; + + +public class LeadControllerUtils { + + /** + * Gets hash code for table using murmur2 function, ignores the most significant bit. + * Note: This method CANNOT be changed when lead controller resource is enabled. + * Otherwise it will assign different controller for the same table, which will mess up the controller periodic tasks and realtime segment completion. + * @param rawTableName table name + * @return hash code ignoring the most significant bit. + */ + private static int getHashCodeForTable(String rawTableName) { + return (HashUtils.murmur2(StringUtil.encodeUtf8(rawTableName)) & 0x7fffffff); + } + + /** + * Given a raw table name and number of partitions, returns the partition id in lead controller resource. + * @param rawTableName raw table name + * @param numPartitions number of partitions + * @return partition id in lead controller resource. + */ + public static int getPartitionIdForTable(String rawTableName, int numPartitions) { + return getHashCodeForTable(rawTableName) % numPartitions; + } + + /** + * Gets lead controller for table from lead controller resource. + * If the resource is disabled or no controller registered as participant, there is no instance in "MASTER" state. + * @param leadControllerResourceExternalView external view of lead controller resource + * @param rawTableName table name without type + * @return leader of partition, null if not found or resource is disabled. + */ + public static String getLeadControllerForTable(ExternalView leadControllerResourceExternalView, String rawTableName) { + if (leadControllerResourceExternalView == null) { + return null; + } + Set<String> partitionSet = leadControllerResourceExternalView.getPartitionSet(); + if (partitionSet == null || partitionSet.isEmpty()) { + return null; + } + int numPartitions = partitionSet.size(); + int partitionIndex = getPartitionIdForTable(rawTableName, numPartitions); + String partitionName = formPartitionName(partitionIndex); + Map<String, String> partitionStateMap = leadControllerResourceExternalView.getStateMap(partitionName); + + // Get master host from partition map. Return null if no master found. + for (Map.Entry<String, String> entry : partitionStateMap.entrySet()) { + if (MasterSlaveSMD.States.MASTER.name().equals(entry.getValue())) { + return entry.getKey(); + } + } + return null; + } + + public static String generateControllerParticipantId(String controllerHost, String controllerPort) { + return org.apache.pinot.common.utils.CommonConstants.Helix.PREFIX_OF_CONTROLLER_INSTANCE + controllerHost + "_" + + controllerPort; + } + + public static String formPartitionName(int partitionIndex) { Review comment: generatePartitionName() to keep the method naming consistent? ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org For additional commands, e-mail: commits-h...@pinot.apache.org
