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KAFKA-21302: Sort copartition groups and indexes for consistent Streams topology comparison #23855

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KAFKA-21302: Sort copartition groups and indexes for consistent Streams topology comparison #23855

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f20def5
KAFKA-21302: Sort copartition groups and indexes for consistent Stre…
chickenchickenlove Oct 18, 2026
b18728e
Addressing review.
chickenchickenlove Oct 20, 2026
2b2398e
Addressing review.
chickenchickenlove Oct 21, 2026
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5 changes: 2 additions & 3 deletions group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2520,16 +2520,15 @@ private StreamsTopology maybeUpdateTopology(final String groupId,
final StreamsGroup group,
final List<CoordinatorRecord> records) {
if (topology != null) {
StreamsTopology streamsTopologyFromRequest = StreamsTopology.fromHeartbeatRequest(topology);
if (group.topology().isEmpty()) {
log.info("[GroupId {}][MemberId {}] Member initialized the topology with epoch {}", groupId, memberId, topology.epoch());
StreamsGroupTopologyValue recordValue = convertToStreamsGroupTopologyRecord(topology);
records.add(newStreamsGroupTopologyRecord(groupId, recordValue));
return streamsTopologyFromRequest;
return StreamsTopology.fromRecord(recordValue);
} else if (group.topology().get().topologyEpoch() > topology.epoch()) {
log.info("[GroupId {}][MemberId {}] Member joined with stale topology epoch {}", groupId, memberId, topology.epoch());
return group.topology().get();
} else if (!group.topology().get().equals(streamsTopologyFromRequest)) {
} else if (!group.topology().get().matches(topology)) {
throw new InvalidRequestException("Topology updates are not supported yet.");
} else {
log.debug("[GroupId {}][MemberId {}] Member joined with currently initialized topology {}", groupId, memberId, topology.epoch());
Expand Down
177 changes: 176 additions & 1 deletion ...coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/StreamsTopology.java
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Original file line number Diff line number Diff line change
Expand Up @@ -19,12 +19,14 @@
import org.apache.kafka.common.message.StreamsGroupDescribeResponseData;
import org.apache.kafka.common.message.StreamsGroupHeartbeatRequestData;
import org.apache.kafka.coordinator.group.generated.StreamsGroupTopologyValue;
import org.apache.kafka.coordinator.group.generated.StreamsGroupTopologyValue.CopartitionGroup;
import org.apache.kafka.coordinator.group.generated.StreamsGroupTopologyValue.Subtopology;
import org.apache.kafka.coordinator.group.generated.StreamsGroupTopologyValue.TopicInfo;

import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
Expand Down Expand Up @@ -111,7 +113,8 @@ public Set<String> requiredTopics() {
public static StreamsTopology fromRecord(StreamsGroupTopologyValue record) {
return new StreamsTopology(
record.epoch(),
record.subtopologies().stream().collect(Collectors.toMap(Subtopology::subtopologyId, x -> x))
record.subtopologies().stream()
.collect(Collectors.toMap(Subtopology::subtopologyId, x -> x))
);
}

Expand All @@ -128,6 +131,178 @@ public static StreamsTopology fromHeartbeatRequest(StreamsGroupHeartbeatRequestD
return new StreamsTopology(topology.epoch(), subtopologyMap);
}

/**
* Checks whether the request describes this topology without converting or modifying it.
* Subtopologies are matched by ID. Copartition groups and their topic indexes are compared
* without regard to order, but duplicate occurrences must still match. All other lists
* retain their order-sensitive comparison, including the topic lists referenced by indexes.
*
* @param topology The topology supplied in the heartbeat request.
* @return Whether the request matches this topology.
*/
public boolean matches(StreamsGroupHeartbeatRequestData.Topology topology) {
if (topologyEpoch != topology.epoch() || subtopologies.size() != topology.subtopologies().size()) {
return false;
}
for (int i = 0; i < topology.subtopologies().size(); i++) {
StreamsGroupHeartbeatRequestData.Subtopology requested = topology.subtopologies().get(i);
Subtopology current = subtopologies.get(requested.subtopologyId());
if (current == null || !matchesSubtopology(current, requested)) {
return false;
}

// Do not let repeated IDs match one stored subtopology while omitting another.
for (int j = 0; j < i; j++) {
if (requested.subtopologyId().equals(topology.subtopologies().get(j).subtopologyId())) {
return false;
}
}
}
return true;
}

// Keep these comparisons in sync with the generated fields guarded by StreamsTopologyTest.
private static boolean matchesSubtopology(Subtopology current, StreamsGroupHeartbeatRequestData.Subtopology requested) {
if (!current.subtopologyId().equals(requested.subtopologyId())) {
return false;
}

return current.sourceTopics().equals(requested.sourceTopics())
&& current.sourceTopicRegex().equals(requested.sourceTopicRegex())
&& current.repartitionSinkTopics().equals(requested.repartitionSinkTopics())
&& matchesTopicInfos(current.repartitionSourceTopics(), requested.repartitionSourceTopics())
&& matchesTopicInfos(current.stateChangelogTopics(), requested.stateChangelogTopics())
&& matchesCopartitionGroups(current.copartitionGroups(), requested.copartitionGroups());
}

private static boolean matchesTopicInfos(List<TopicInfo> current, List<StreamsGroupHeartbeatRequestData.TopicInfo> requested) {
if (current.size() != requested.size()) {
return false;
}
for (int i = 0; i < current.size(); i++) {
TopicInfo fromCurrent = current.get(i);
StreamsGroupHeartbeatRequestData.TopicInfo fromRequested = requested.get(i);
if (!fromCurrent.name().equals(fromRequested.name())
|| fromCurrent.partitions() != fromRequested.partitions()
|| fromCurrent.replicationFactor() != fromRequested.replicationFactor()
|| !matchesTopicConfigs(fromCurrent.topicConfigs(), fromRequested.topicConfigs())) {
return false;
}
}
return true;
}

private static boolean matchesTopicConfigs(
List<StreamsGroupTopologyValue.TopicConfig> current,
List<StreamsGroupHeartbeatRequestData.KeyValue> requested
) {
// Preserve the null handling of convertToTopicInfo for directly constructed requests.
if (current == null || requested == null) {
return current == null && requested == null;
}
if (current.size() != requested.size()) {
return false;
}
for (int i = 0; i < current.size(); i++) {
if (!Objects.equals(current.get(i).key(), requested.get(i).key())
|| !Objects.equals(current.get(i).value(), requested.get(i).value())) {
return false;
}
}
return true;
}

private static boolean matchesCopartitionGroups(
List<CopartitionGroup> current,
List<StreamsGroupHeartbeatRequestData.CopartitionGroup> requested
) {
if (current.size() != requested.size()) {
return false;
}

boolean sameOrder = true;
for (int i = 0; i < current.size(); i++) {
if (!matchesCopartitionGroup(current.get(i), requested.get(i))) {
sameOrder = false;
break;
}
}
if (sameOrder) {
return true;
}

// Count equivalent occurrences rather than allocating sorted copies
// or sets, which would lose duplicate groups.
for (int i = 0; i < current.size(); i++) {
CopartitionGroup group = current.get(i);
StreamsGroupHeartbeatRequestData.CopartitionGroup representative = null;
int requestedCount = 0;
for (int j = 0; j < requested.size(); j++) {
if (matchesCopartitionGroup(group, requested.get(j))) {
representative = requested.get(j);
requestedCount++;
}
}
if (representative == null) {
return false;
}
int currentCount = 0;
for (int j = 0; j < current.size(); j++) {
if (matchesCopartitionGroup(current.get(j), representative)) {
currentCount++;
}
}
if (currentCount != requestedCount) {
return false;
}
}
return true;
}

private static boolean matchesCopartitionGroup(
CopartitionGroup current,
StreamsGroupHeartbeatRequestData.CopartitionGroup requested
) {
return sameTopicIndexes(current.sourceTopics(), requested.sourceTopics())
&& sameTopicIndexes(current.sourceTopicRegex(), requested.sourceTopicRegex())
&& sameTopicIndexes(current.repartitionSourceTopics(), requested.repartitionSourceTopics());
}

private static boolean sameTopicIndexes(List<Short> current, List<Short> requested) {
// [0] != [0, 1, 2]
if (current.size() != requested.size()) {
return false;
}

// [0, 1, 2] == [0, 1, 2]
if (current.equals(requested)) {
return true;
}

int size = current.size();

// Ignore ordering while preserving duplicate counts.
// For example, [0, 0, 1] matches [1, 0, 0], but not [0, 1, 1].
for (int i = 0; i < size; i++) {
short index = current.get(i);
int currentCount = 0;
int requestedCount = 0;

for (int j = 0; j < size; j++) {
if (current.get(j) == index) {
currentCount++;
}
if (requested.get(j) == index) {
requestedCount++;
}
}
if (currentCount != requestedCount) {
return false;
}
}
return true;
}

public StreamsGroupDescribeResponseData.Topology asStreamsGroupDescribeTopology() {
return new StreamsGroupDescribeResponseData.Topology()
.setEpoch(topologyEpoch)
Expand Down
104 changes: 104 additions & 0 deletions ...oordinator/src/test/java/org/apache/kafka/coordinator/group/GroupMetadataManagerTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -129,6 +129,7 @@
import org.apache.kafka.coordinator.group.generated.StreamsGroupMetadataKey;
import org.apache.kafka.coordinator.group.generated.StreamsGroupMetadataValue;
import org.apache.kafka.coordinator.group.generated.StreamsGroupTargetAssignmentMemberKey;
import org.apache.kafka.coordinator.group.generated.StreamsGroupTopologyKey;
import org.apache.kafka.coordinator.group.generated.StreamsGroupTopologyValue;
import org.apache.kafka.coordinator.group.metrics.GroupCoordinatorMetricsShard;
import org.apache.kafka.coordinator.group.modern.Assignment;
Expand Down Expand Up @@ -21330,6 +21331,109 @@ barTopicName, computeTopicHash(barTopicName, metadataImage)
assertRecordsEquals(expectedRecords, result.records());
}

@Test
public void testStreamsGroupMemberJoiningWithReorderedCopartitionGroups() {
// First - [[3, 2], [1, 0]]
// Second - [[1, 0], [2, 3]]
String groupId = "fooup";
String memberId = Uuid.randomUuid().toString();
Topology topology = new Topology().setSubtopologies(List.of(
new Subtopology()
.setSubtopologyId("subtopology1")
.setSourceTopics(List.of("foo", "bar", "baz", "qux"))
.setCopartitionGroups(List.of(
new CopartitionGroup().setSourceTopics(List.of((short) 3, (short) 2)),
new CopartitionGroup().setSourceTopics(List.of((short) 1, (short) 0))
))
));
MockTaskAssignor assignor = new MockTaskAssignor("sticky");
GroupMetadataManagerTestContext context = new GroupMetadataManagerTestContext.Builder()
.withStreamsGroupTaskAssignors(List.of(assignor))
.withMetadataImage(new MetadataImageBuilder()
.addTopic(Uuid.randomUuid(), "foo", 3)
.addTopic(Uuid.randomUuid(), "bar", 3)
.addTopic(Uuid.randomUuid(), "baz", 3)
.addTopic(Uuid.randomUuid(), "qux", 3)
.buildCoordinatorMetadataImage())
.withConfig(GroupCoordinatorConfig.STREAMS_GROUP_INITIAL_REBALANCE_DELAY_MS_CONFIG, 0)
.build();
assignor.prepareGroupAssignment(Map.of(memberId, TasksTuple.EMPTY));
context.replay(StreamsCoordinatorRecordHelpers.newStreamsGroupTopologyRecord(groupId, topology));

Topology reorderedTopology = topology.duplicate();
reorderedTopology.subtopologies().get(0).setCopartitionGroups(List.of(
new CopartitionGroup().setSourceTopics(List.of((short) 1, (short) 0)),
new CopartitionGroup().setSourceTopics(List.of((short) 2, (short) 3))
));
CoordinatorResult<StreamsGroupHeartbeatResult, CoordinatorRecord> result = context.streamsGroupHeartbeat(
new StreamsGroupHeartbeatRequestData()
.setGroupId(groupId)
.setMemberId(memberId)
.setMemberEpoch(0)
.setRebalanceTimeoutMs(1500)
.setTopology(reorderedTopology)
.setProcessId(DEFAULT_PROCESS_ID)
.setActiveTasks(List.of())
.setStandbyTasks(List.of())
.setWarmupTasks(List.of()));

@lucasbru lucasbru Oct 20, 2026

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Maybe also assert that result.records() contains no new topology record, so we know the request was matched against the existing topology?


assertEquals(Errors.NONE.code(), result.response().data().errorCode());
assertTrue(result.response().data().memberEpoch() > 0);
assertTrue(result.records().stream().noneMatch(
record -> record.key() instanceof StreamsGroupTopologyKey)
);
}

@Test
public void testStreamsGroupMemberJoiningWithDifferentCopartitionGroups() {
// First -> [[0, 1], [2, 3]]
// Second -> [[0, 2], [1, 3]]
String groupId = "fooup";
String memberId = Uuid.randomUuid().toString();
Topology topology = new Topology().setEpoch(1).setSubtopologies(List.of(
new Subtopology()
.setSubtopologyId("subtopology1")
.setSourceTopics(List.of("foo", "bar", "baz", "qux"))
.setCopartitionGroups(List.of(
new CopartitionGroup().setSourceTopics(List.of((short) 0, (short) 1)),
new CopartitionGroup().setSourceTopics(List.of((short) 2, (short) 3))
))
));
MockTaskAssignor assignor = new MockTaskAssignor("sticky");
GroupMetadataManagerTestContext context = new GroupMetadataManagerTestContext.Builder()
.withStreamsGroupTaskAssignors(List.of(assignor))
.withMetadataImage(new MetadataImageBuilder()
.addTopic(Uuid.randomUuid(), "foo", 3)
.addTopic(Uuid.randomUuid(), "bar", 3)
.addTopic(Uuid.randomUuid(), "baz", 3)
.addTopic(Uuid.randomUuid(), "qux", 3)
.buildCoordinatorMetadataImage())
.withConfig(GroupCoordinatorConfig.STREAMS_GROUP_INITIAL_REBALANCE_DELAY_MS_CONFIG, 0)
.build();
assignor.prepareGroupAssignment(Map.of(memberId, TasksTuple.EMPTY));
context.replay(StreamsCoordinatorRecordHelpers.newStreamsGroupTopologyRecord(groupId, topology));

// Keep the epoch and topics unchanged, but change which topics must be copartitioned.
Topology changedTopology = topology.duplicate();
changedTopology.subtopologies().get(0).setCopartitionGroups(List.of(
new CopartitionGroup().setSourceTopics(List.of((short) 0, (short) 2)),
new CopartitionGroup().setSourceTopics(List.of((short) 1, (short) 3))
));
InvalidRequestException exception = assertThrows(InvalidRequestException.class, () -> context.streamsGroupHeartbeat(
new StreamsGroupHeartbeatRequestData()
.setGroupId(groupId)
.setMemberId(memberId)
.setMemberEpoch(0)
.setRebalanceTimeoutMs(1500)
.setTopology(changedTopology)
.setProcessId(DEFAULT_PROCESS_ID)
.setActiveTasks(List.of())
.setStandbyTasks(List.of())
.setWarmupTasks(List.of())));

assertEquals("Topology updates are not supported yet.", exception.getMessage());
}

@Test
public void testStreamsGroupMemberJoiningWithStaleTopology() {
String groupId = "fooup";
Expand Down
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