AndrewJSchofield commented on code in PR #18864: URL: https://github.com/apache/kafka/pull/18864#discussion_r1958257137
########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/assignor/SimpleAssignor.java: ########## @@ -72,36 +77,178 @@ private GroupAssignment assignHomogenous( if (subscribeTopicIds.isEmpty()) return new GroupAssignment(Collections.emptyMap()); - Map<Uuid, Set<Integer>> targetPartitions = computeTargetPartitions( + // Subscribed topic partitions for the share group. + List<TargetPartition> targetPartitions = computeTargetPartitions( subscribeTopicIds, subscribedTopicDescriber); - return new GroupAssignment(groupSpec.memberIds().stream().collect(Collectors.toMap( - Function.identity(), memberId -> new MemberAssignmentImpl(targetPartitions)))); + // The current assignment from topic partition to members. + Map<TargetPartition, List<String>> currentAssignment = currentAssignment(groupSpec); + return newAssignmentHomogeneous(groupSpec, subscribeTopicIds, targetPartitions, currentAssignment); } private GroupAssignment assignHeterogeneous( GroupSpec groupSpec, SubscribedTopicDescriber subscribedTopicDescriber ) { - Map<String, MemberAssignment> members = new HashMap<>(); + Map<String, List<TargetPartition>> memberToPartitionsSubscription = new HashMap<>(); for (String memberId : groupSpec.memberIds()) { MemberSubscription spec = groupSpec.memberSubscription(memberId); if (spec.subscribedTopicIds().isEmpty()) continue; - Map<Uuid, Set<Integer>> targetPartitions = computeTargetPartitions( + // Subscribed topic partitions for the share group member. + List<TargetPartition> targetPartitions = computeTargetPartitions( spec.subscribedTopicIds(), subscribedTopicDescriber); + memberToPartitionsSubscription.put(memberId, targetPartitions); + } + + // The current assignment from topic partition to members. + Map<TargetPartition, List<String>> currentAssignment = currentAssignment(groupSpec); + return newAssignmentHeterogeneous(groupSpec, memberToPartitionsSubscription, currentAssignment); + } - members.put(memberId, new MemberAssignmentImpl(targetPartitions)); + // Get the current assignment for subscribed topic partitions to share group members. + private Map<TargetPartition, List<String>> currentAssignment(GroupSpec groupSpec) { + Map<TargetPartition, List<String>> assignment = new HashMap<>(); + + for (String member : groupSpec.memberIds()) { + Map<Uuid, Set<Integer>> assignedTopicPartitions = groupSpec.memberAssignment(member).partitions(); + assignedTopicPartitions.forEach((topicId, partitions) -> partitions.forEach( + partition -> assignment.computeIfAbsent(new TargetPartition(topicId, partition), k -> new ArrayList<>()).add(member))); } + return assignment; + } + + private GroupAssignment newAssignmentHomogeneous( + GroupSpec groupSpec, + Set<Uuid> subscribeTopicIds, + List<TargetPartition> targetPartitions, + Map<TargetPartition, List<String>> currentAssignment) { + + Map<TargetPartition, List<String>> newAssignment = new HashMap<>(); + // Step 1: Hash member IDs to partitions. Review Comment: Blank line before this comment please. ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/assignor/SimpleAssignor.java: ########## @@ -72,36 +77,178 @@ private GroupAssignment assignHomogenous( if (subscribeTopicIds.isEmpty()) return new GroupAssignment(Collections.emptyMap()); - Map<Uuid, Set<Integer>> targetPartitions = computeTargetPartitions( + // Subscribed topic partitions for the share group. + List<TargetPartition> targetPartitions = computeTargetPartitions( subscribeTopicIds, subscribedTopicDescriber); - return new GroupAssignment(groupSpec.memberIds().stream().collect(Collectors.toMap( - Function.identity(), memberId -> new MemberAssignmentImpl(targetPartitions)))); + // The current assignment from topic partition to members. + Map<TargetPartition, List<String>> currentAssignment = currentAssignment(groupSpec); + return newAssignmentHomogeneous(groupSpec, subscribeTopicIds, targetPartitions, currentAssignment); } private GroupAssignment assignHeterogeneous( GroupSpec groupSpec, SubscribedTopicDescriber subscribedTopicDescriber ) { - Map<String, MemberAssignment> members = new HashMap<>(); + Map<String, List<TargetPartition>> memberToPartitionsSubscription = new HashMap<>(); for (String memberId : groupSpec.memberIds()) { MemberSubscription spec = groupSpec.memberSubscription(memberId); if (spec.subscribedTopicIds().isEmpty()) continue; - Map<Uuid, Set<Integer>> targetPartitions = computeTargetPartitions( + // Subscribed topic partitions for the share group member. + List<TargetPartition> targetPartitions = computeTargetPartitions( spec.subscribedTopicIds(), subscribedTopicDescriber); + memberToPartitionsSubscription.put(memberId, targetPartitions); + } + + // The current assignment from topic partition to members. + Map<TargetPartition, List<String>> currentAssignment = currentAssignment(groupSpec); + return newAssignmentHeterogeneous(groupSpec, memberToPartitionsSubscription, currentAssignment); + } - members.put(memberId, new MemberAssignmentImpl(targetPartitions)); + // Get the current assignment for subscribed topic partitions to share group members. + private Map<TargetPartition, List<String>> currentAssignment(GroupSpec groupSpec) { + Map<TargetPartition, List<String>> assignment = new HashMap<>(); + + for (String member : groupSpec.memberIds()) { + Map<Uuid, Set<Integer>> assignedTopicPartitions = groupSpec.memberAssignment(member).partitions(); + assignedTopicPartitions.forEach((topicId, partitions) -> partitions.forEach( + partition -> assignment.computeIfAbsent(new TargetPartition(topicId, partition), k -> new ArrayList<>()).add(member))); } + return assignment; + } + + private GroupAssignment newAssignmentHomogeneous( + GroupSpec groupSpec, + Set<Uuid> subscribeTopicIds, + List<TargetPartition> targetPartitions, + Map<TargetPartition, List<String>> currentAssignment) { + + Map<TargetPartition, List<String>> newAssignment = new HashMap<>(); + // Step 1: Hash member IDs to partitions. + memberHashAssignment(targetPartitions, groupSpec.memberIds(), newAssignment); + + // Step 2: Round-robin assignment for unassigned partitions which do not have members already assigned in the current assignment. + Set<TargetPartition> assignedPartitions = new HashSet<>(newAssignment.keySet()); + List<TargetPartition> unassignedPartitions = targetPartitions.stream() + .filter(targetPartition -> !assignedPartitions.contains(targetPartition)) + .filter(targetPartition -> !currentAssignment.containsKey(targetPartition)) + .collect(Collectors.toList()); Review Comment: The `.collect(Collectors.toList())` can be replaced with `.toList()`. ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/assignor/SimpleAssignor.java: ########## @@ -72,36 +77,178 @@ private GroupAssignment assignHomogenous( if (subscribeTopicIds.isEmpty()) return new GroupAssignment(Collections.emptyMap()); - Map<Uuid, Set<Integer>> targetPartitions = computeTargetPartitions( + // Subscribed topic partitions for the share group. + List<TargetPartition> targetPartitions = computeTargetPartitions( subscribeTopicIds, subscribedTopicDescriber); - return new GroupAssignment(groupSpec.memberIds().stream().collect(Collectors.toMap( - Function.identity(), memberId -> new MemberAssignmentImpl(targetPartitions)))); + // The current assignment from topic partition to members. + Map<TargetPartition, List<String>> currentAssignment = currentAssignment(groupSpec); + return newAssignmentHomogeneous(groupSpec, subscribeTopicIds, targetPartitions, currentAssignment); } private GroupAssignment assignHeterogeneous( GroupSpec groupSpec, SubscribedTopicDescriber subscribedTopicDescriber ) { - Map<String, MemberAssignment> members = new HashMap<>(); + Map<String, List<TargetPartition>> memberToPartitionsSubscription = new HashMap<>(); for (String memberId : groupSpec.memberIds()) { MemberSubscription spec = groupSpec.memberSubscription(memberId); if (spec.subscribedTopicIds().isEmpty()) continue; - Map<Uuid, Set<Integer>> targetPartitions = computeTargetPartitions( + // Subscribed topic partitions for the share group member. + List<TargetPartition> targetPartitions = computeTargetPartitions( spec.subscribedTopicIds(), subscribedTopicDescriber); + memberToPartitionsSubscription.put(memberId, targetPartitions); + } + + // The current assignment from topic partition to members. + Map<TargetPartition, List<String>> currentAssignment = currentAssignment(groupSpec); + return newAssignmentHeterogeneous(groupSpec, memberToPartitionsSubscription, currentAssignment); + } - members.put(memberId, new MemberAssignmentImpl(targetPartitions)); + // Get the current assignment for subscribed topic partitions to share group members. + private Map<TargetPartition, List<String>> currentAssignment(GroupSpec groupSpec) { + Map<TargetPartition, List<String>> assignment = new HashMap<>(); + + for (String member : groupSpec.memberIds()) { + Map<Uuid, Set<Integer>> assignedTopicPartitions = groupSpec.memberAssignment(member).partitions(); + assignedTopicPartitions.forEach((topicId, partitions) -> partitions.forEach( + partition -> assignment.computeIfAbsent(new TargetPartition(topicId, partition), k -> new ArrayList<>()).add(member))); } + return assignment; + } + + private GroupAssignment newAssignmentHomogeneous( + GroupSpec groupSpec, + Set<Uuid> subscribeTopicIds, + List<TargetPartition> targetPartitions, + Map<TargetPartition, List<String>> currentAssignment) { + + Map<TargetPartition, List<String>> newAssignment = new HashMap<>(); + // Step 1: Hash member IDs to partitions. + memberHashAssignment(targetPartitions, groupSpec.memberIds(), newAssignment); + + // Step 2: Round-robin assignment for unassigned partitions which do not have members already assigned in the current assignment. + Set<TargetPartition> assignedPartitions = new HashSet<>(newAssignment.keySet()); + List<TargetPartition> unassignedPartitions = targetPartitions.stream() + .filter(targetPartition -> !assignedPartitions.contains(targetPartition)) + .filter(targetPartition -> !currentAssignment.containsKey(targetPartition)) + .collect(Collectors.toList()); + + roundRobinAssignment(groupSpec.memberIds(), unassignedPartitions, newAssignment); + + Map<String, Set<TargetPartition>> finalAssignment = new HashMap<>(); + + // When combining current assignment, we need to only consider the topics in current assignment that are also being + // subscribed in the new assignment as well. + currentAssignment.forEach((targetPartition, members) -> { + if (subscribeTopicIds.contains(targetPartition.topicId)) + members.forEach(member -> { + if (groupSpec.memberIds().contains(member)) + finalAssignment.computeIfAbsent(member, k -> new HashSet<>()).add(targetPartition); + }); + }); + newAssignment.forEach((targetPartition, members) -> members.forEach(member -> + finalAssignment.computeIfAbsent(member, k -> new HashSet<>()).add(targetPartition))); + + return groupAssignment(finalAssignment, groupSpec.memberIds()); + } + + private GroupAssignment newAssignmentHeterogeneous( + GroupSpec groupSpec, + Map<String, List<TargetPartition>> memberToPartitionsSubscription, + Map<TargetPartition, List<String>> currentAssignment) { + + // Exhaustive set of all subscribed topic partitions. + Set<TargetPartition> targetPartitions = new LinkedHashSet<>(); + memberToPartitionsSubscription.values().forEach(targetPartitions::addAll); + + // Create a map for topic to members subscription. + Map<Uuid, Set<String>> topicToMemberSubscription = new HashMap<>(); + memberToPartitionsSubscription.forEach((member, partitions) -> + partitions.forEach(partition -> topicToMemberSubscription.computeIfAbsent(partition.topicId(), k -> new LinkedHashSet<>()).add(member))); + + Map<TargetPartition, List<String>> newAssignment = new HashMap<>(); + // Step 1: Hash member IDs to partitions. Review Comment: Blank line before this comment please. ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/assignor/SimpleAssignor.java: ########## @@ -72,36 +77,178 @@ private GroupAssignment assignHomogenous( if (subscribeTopicIds.isEmpty()) Review Comment: This should be better named `subscribedTopicIds`. ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/assignor/SimpleAssignor.java: ########## @@ -72,36 +77,178 @@ private GroupAssignment assignHomogenous( if (subscribeTopicIds.isEmpty()) return new GroupAssignment(Collections.emptyMap()); - Map<Uuid, Set<Integer>> targetPartitions = computeTargetPartitions( + // Subscribed topic partitions for the share group. + List<TargetPartition> targetPartitions = computeTargetPartitions( subscribeTopicIds, subscribedTopicDescriber); - return new GroupAssignment(groupSpec.memberIds().stream().collect(Collectors.toMap( - Function.identity(), memberId -> new MemberAssignmentImpl(targetPartitions)))); + // The current assignment from topic partition to members. + Map<TargetPartition, List<String>> currentAssignment = currentAssignment(groupSpec); + return newAssignmentHomogeneous(groupSpec, subscribeTopicIds, targetPartitions, currentAssignment); } private GroupAssignment assignHeterogeneous( GroupSpec groupSpec, SubscribedTopicDescriber subscribedTopicDescriber ) { - Map<String, MemberAssignment> members = new HashMap<>(); + Map<String, List<TargetPartition>> memberToPartitionsSubscription = new HashMap<>(); for (String memberId : groupSpec.memberIds()) { MemberSubscription spec = groupSpec.memberSubscription(memberId); if (spec.subscribedTopicIds().isEmpty()) continue; - Map<Uuid, Set<Integer>> targetPartitions = computeTargetPartitions( + // Subscribed topic partitions for the share group member. + List<TargetPartition> targetPartitions = computeTargetPartitions( spec.subscribedTopicIds(), subscribedTopicDescriber); + memberToPartitionsSubscription.put(memberId, targetPartitions); + } + + // The current assignment from topic partition to members. + Map<TargetPartition, List<String>> currentAssignment = currentAssignment(groupSpec); + return newAssignmentHeterogeneous(groupSpec, memberToPartitionsSubscription, currentAssignment); + } - members.put(memberId, new MemberAssignmentImpl(targetPartitions)); + // Get the current assignment for subscribed topic partitions to share group members. + private Map<TargetPartition, List<String>> currentAssignment(GroupSpec groupSpec) { + Map<TargetPartition, List<String>> assignment = new HashMap<>(); + + for (String member : groupSpec.memberIds()) { + Map<Uuid, Set<Integer>> assignedTopicPartitions = groupSpec.memberAssignment(member).partitions(); + assignedTopicPartitions.forEach((topicId, partitions) -> partitions.forEach( + partition -> assignment.computeIfAbsent(new TargetPartition(topicId, partition), k -> new ArrayList<>()).add(member))); } + return assignment; + } + + private GroupAssignment newAssignmentHomogeneous( + GroupSpec groupSpec, + Set<Uuid> subscribeTopicIds, + List<TargetPartition> targetPartitions, + Map<TargetPartition, List<String>> currentAssignment) { + + Map<TargetPartition, List<String>> newAssignment = new HashMap<>(); + // Step 1: Hash member IDs to partitions. + memberHashAssignment(targetPartitions, groupSpec.memberIds(), newAssignment); + + // Step 2: Round-robin assignment for unassigned partitions which do not have members already assigned in the current assignment. + Set<TargetPartition> assignedPartitions = new HashSet<>(newAssignment.keySet()); + List<TargetPartition> unassignedPartitions = targetPartitions.stream() + .filter(targetPartition -> !assignedPartitions.contains(targetPartition)) + .filter(targetPartition -> !currentAssignment.containsKey(targetPartition)) + .collect(Collectors.toList()); + + roundRobinAssignment(groupSpec.memberIds(), unassignedPartitions, newAssignment); + + Map<String, Set<TargetPartition>> finalAssignment = new HashMap<>(); + + // When combining current assignment, we need to only consider the topics in current assignment that are also being + // subscribed in the new assignment as well. + currentAssignment.forEach((targetPartition, members) -> { + if (subscribeTopicIds.contains(targetPartition.topicId)) + members.forEach(member -> { + if (groupSpec.memberIds().contains(member)) + finalAssignment.computeIfAbsent(member, k -> new HashSet<>()).add(targetPartition); + }); + }); + newAssignment.forEach((targetPartition, members) -> members.forEach(member -> + finalAssignment.computeIfAbsent(member, k -> new HashSet<>()).add(targetPartition))); + + return groupAssignment(finalAssignment, groupSpec.memberIds()); + } + + private GroupAssignment newAssignmentHeterogeneous( + GroupSpec groupSpec, + Map<String, List<TargetPartition>> memberToPartitionsSubscription, + Map<TargetPartition, List<String>> currentAssignment) { + + // Exhaustive set of all subscribed topic partitions. + Set<TargetPartition> targetPartitions = new LinkedHashSet<>(); + memberToPartitionsSubscription.values().forEach(targetPartitions::addAll); + + // Create a map for topic to members subscription. + Map<Uuid, Set<String>> topicToMemberSubscription = new HashMap<>(); + memberToPartitionsSubscription.forEach((member, partitions) -> + partitions.forEach(partition -> topicToMemberSubscription.computeIfAbsent(partition.topicId(), k -> new LinkedHashSet<>()).add(member))); + + Map<TargetPartition, List<String>> newAssignment = new HashMap<>(); + // Step 1: Hash member IDs to partitions. + memberToPartitionsSubscription.forEach((member, partitions) -> + memberHashAssignment(partitions, Collections.singletonList(member), newAssignment)); Review Comment: `List.of` ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/assignor/SimpleAssignor.java: ########## @@ -72,36 +77,178 @@ private GroupAssignment assignHomogenous( if (subscribeTopicIds.isEmpty()) return new GroupAssignment(Collections.emptyMap()); - Map<Uuid, Set<Integer>> targetPartitions = computeTargetPartitions( + // Subscribed topic partitions for the share group. + List<TargetPartition> targetPartitions = computeTargetPartitions( subscribeTopicIds, subscribedTopicDescriber); - return new GroupAssignment(groupSpec.memberIds().stream().collect(Collectors.toMap( - Function.identity(), memberId -> new MemberAssignmentImpl(targetPartitions)))); + // The current assignment from topic partition to members. + Map<TargetPartition, List<String>> currentAssignment = currentAssignment(groupSpec); + return newAssignmentHomogeneous(groupSpec, subscribeTopicIds, targetPartitions, currentAssignment); } private GroupAssignment assignHeterogeneous( GroupSpec groupSpec, SubscribedTopicDescriber subscribedTopicDescriber ) { - Map<String, MemberAssignment> members = new HashMap<>(); + Map<String, List<TargetPartition>> memberToPartitionsSubscription = new HashMap<>(); for (String memberId : groupSpec.memberIds()) { MemberSubscription spec = groupSpec.memberSubscription(memberId); if (spec.subscribedTopicIds().isEmpty()) continue; - Map<Uuid, Set<Integer>> targetPartitions = computeTargetPartitions( + // Subscribed topic partitions for the share group member. + List<TargetPartition> targetPartitions = computeTargetPartitions( spec.subscribedTopicIds(), subscribedTopicDescriber); + memberToPartitionsSubscription.put(memberId, targetPartitions); + } + + // The current assignment from topic partition to members. + Map<TargetPartition, List<String>> currentAssignment = currentAssignment(groupSpec); + return newAssignmentHeterogeneous(groupSpec, memberToPartitionsSubscription, currentAssignment); + } - members.put(memberId, new MemberAssignmentImpl(targetPartitions)); + // Get the current assignment for subscribed topic partitions to share group members. + private Map<TargetPartition, List<String>> currentAssignment(GroupSpec groupSpec) { + Map<TargetPartition, List<String>> assignment = new HashMap<>(); + + for (String member : groupSpec.memberIds()) { + Map<Uuid, Set<Integer>> assignedTopicPartitions = groupSpec.memberAssignment(member).partitions(); + assignedTopicPartitions.forEach((topicId, partitions) -> partitions.forEach( + partition -> assignment.computeIfAbsent(new TargetPartition(topicId, partition), k -> new ArrayList<>()).add(member))); } + return assignment; + } + + private GroupAssignment newAssignmentHomogeneous( + GroupSpec groupSpec, + Set<Uuid> subscribeTopicIds, + List<TargetPartition> targetPartitions, + Map<TargetPartition, List<String>> currentAssignment) { + + Map<TargetPartition, List<String>> newAssignment = new HashMap<>(); + // Step 1: Hash member IDs to partitions. + memberHashAssignment(targetPartitions, groupSpec.memberIds(), newAssignment); + + // Step 2: Round-robin assignment for unassigned partitions which do not have members already assigned in the current assignment. + Set<TargetPartition> assignedPartitions = new HashSet<>(newAssignment.keySet()); + List<TargetPartition> unassignedPartitions = targetPartitions.stream() + .filter(targetPartition -> !assignedPartitions.contains(targetPartition)) + .filter(targetPartition -> !currentAssignment.containsKey(targetPartition)) + .collect(Collectors.toList()); + + roundRobinAssignment(groupSpec.memberIds(), unassignedPartitions, newAssignment); + + Map<String, Set<TargetPartition>> finalAssignment = new HashMap<>(); + + // When combining current assignment, we need to only consider the topics in current assignment that are also being Review Comment: This code to combine the current assignment with the new assignment to create the final assignment can be in common I think. -- This is an automated message from the Apache Git Service. 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