showuon commented on a change in pull request #10509: URL: https://github.com/apache/kafka/pull/10509#discussion_r625598009
########## File path: clients/src/main/java/org/apache/kafka/clients/consumer/internals/AbstractStickyAssignor.java ########## @@ -163,127 +159,180 @@ private boolean allSubscriptionsEqual(Set<String> allTopics, */ private Map<String, List<TopicPartition>> constrainedAssign(Map<String, Integer> partitionsPerTopic, Map<String, List<TopicPartition>> consumerToOwnedPartitions) { - SortedSet<TopicPartition> unassignedPartitions = getTopicPartitions(partitionsPerTopic); + if (log.isDebugEnabled()) { + log.debug("performing constrained assign. partitionsPerTopic: {}, consumerToOwnedPartitions: {}", + partitionsPerTopic, consumerToOwnedPartitions); + } Set<TopicPartition> allRevokedPartitions = new HashSet<>(); - // Each consumer should end up in exactly one of the below - // the consumers not yet at capacity + // the consumers not yet at expected capacity List<String> unfilledMembers = new LinkedList<>(); - // the members with exactly maxQuota partitions assigned - Queue<String> maxCapacityMembers = new LinkedList<>(); - // the members with exactly minQuota partitions assigned - Queue<String> minCapacityMembers = new LinkedList<>(); int numberOfConsumers = consumerToOwnedPartitions.size(); - int minQuota = (int) Math.floor(((double) unassignedPartitions.size()) / numberOfConsumers); - int maxQuota = (int) Math.ceil(((double) unassignedPartitions.size()) / numberOfConsumers); + int totalPartitionsCount = partitionsPerTopic.values().stream().reduce(0, Integer::sum); + + int minQuota = (int) Math.floor(((double) totalPartitionsCount) / numberOfConsumers); + int maxQuota = (int) Math.ceil(((double) totalPartitionsCount) / numberOfConsumers); + // the expected number of members with maxQuota assignment + int numExpectedMaxCapacityMembers = totalPartitionsCount % numberOfConsumers; + // the number of members with exactly maxQuota partitions assigned + int numMaxCapacityMembers = 0; - // initialize the assignment map with an empty array of size minQuota for all members + // initialize the assignment map with an empty array of size maxQuota for all members Map<String, List<TopicPartition>> assignment = new HashMap<>( - consumerToOwnedPartitions.keySet().stream().collect(Collectors.toMap(c -> c, c -> new ArrayList<>(minQuota)))); + consumerToOwnedPartitions.keySet().stream().collect(Collectors.toMap(c -> c, c -> new ArrayList<>(maxQuota)))); + List<TopicPartition> assignedPartitions = new ArrayList<>(); // Reassign as many previously owned partitions as possible for (Map.Entry<String, List<TopicPartition>> consumerEntry : consumerToOwnedPartitions.entrySet()) { String consumer = consumerEntry.getKey(); List<TopicPartition> ownedPartitions = consumerEntry.getValue(); List<TopicPartition> consumerAssignment = assignment.get(consumer); - int i = 0; - // assign the first N partitions up to the max quota, and mark the remaining as being revoked - for (TopicPartition tp : ownedPartitions) { - if (i < maxQuota) { - consumerAssignment.add(tp); - unassignedPartitions.remove(tp); - } else { - allRevokedPartitions.add(tp); - } - ++i; - } if (ownedPartitions.size() < minQuota) { + // the expected assignment size is more than consumer have now, so keep all the owned partitions + // and put this member into unfilled member list + if (ownedPartitions.size() > 0) { + consumerAssignment.addAll(ownedPartitions); + assignedPartitions.addAll(ownedPartitions); + } unfilledMembers.add(consumer); + } else if (ownedPartitions.size() >= maxQuota && numMaxCapacityMembers < numExpectedMaxCapacityMembers) { + // consumer owned the "maxQuota" of partitions or more, and we're still under the number of expected max capacity members + // so keep "maxQuota" of the owned partitions, and revoke the rest of the partitions + numMaxCapacityMembers++; + List<TopicPartition> maxQuotaPartitions = ownedPartitions.subList(0, maxQuota); + consumerAssignment.addAll(maxQuotaPartitions); + assignedPartitions.addAll(maxQuotaPartitions); + allRevokedPartitions.addAll(ownedPartitions.subList(maxQuota, ownedPartitions.size())); } else { - // It's possible for a consumer to be at both min and max capacity if minQuota == maxQuota - if (consumerAssignment.size() == minQuota) - minCapacityMembers.add(consumer); - if (consumerAssignment.size() == maxQuota) - maxCapacityMembers.add(consumer); + // consumer owned at least "minQuota" of partitions but we're already at the allowed number of max capacity members Review comment: Yes, this could happen, and just updated. Also the renaming is better. Thanks. -- 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