Skip to content

KAFKA-19362: Finalize homogeneous simple share assignor #19977

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 8 commits into from
Jun 20, 2025
Merged

KAFKA-19362: Finalize homogeneous simple share assignor #19977

Changes from 1 commit
Commits
Show all changes
8 commits
Select commit Hold shift + click to select a range
89ac45f
KAFKA-19362: Finalize homogeneous simple share assignor
AndrewJSchofield Jun 17, 2025
485bde4
Spotless
AndrewJSchofield Jun 17, 2025
c5ee90e
Checkstyle
AndrewJSchofield Jun 17, 2025
2dad1c1
More refinement
AndrewJSchofield Jun 18, 2025
2976d8d
Improve comments.
AndrewJSchofield Jun 18, 2025
c7ee1a7
Correct removal from overfilled members
AndrewJSchofield Jun 18, 2025
de47226
Correct comments
AndrewJSchofield Jun 19, 2025
7088051
Review comments
AndrewJSchofield Jun 20, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
89 changes: 35 additions & 54 deletions .../java/org/apache/kafka/coordinator/group/assignor/SimpleHomogeneousAssignmentBuilder.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -196,10 +196,10 @@ public GroupAssignment build() {

revokeUnassignablePartitions();

revokeOversharedPartitions();

revokeOverfilledMembers();

revokeOversharedPartitions();

// Add in any partitions which are currently not in the assignment.
targetPartitions.forEach(topicPartition -> finalAssignmentByPartition.computeIfAbsent(topicPartition, k -> new HashSet<>()));

Expand Down Expand Up @@ -274,7 +274,32 @@ private void revokeUnassignablePartitions() {
}

/**
* Revoke any over-shared partitions. Prefer to revoke from overfilled members first.
* Revoke partitions from members which are overfilled.
*/
private void revokeOverfilledMembers() {
if (overfilledMembers.isEmpty())
return;

overfilledMembers.forEach(memberIndex -> {
int memberDesiredAssignmentCount = desiredAssignmentCount[memberIndex];
Set<TopicIdPartition> memberFinalAssignment = finalAssignmentByMember.get(memberIndex);
if (memberFinalAssignment.size() > memberDesiredAssignmentCount) {
Iterator<TopicIdPartition> iterator = memberFinalAssignment.iterator();
while (iterator.hasNext()) {
TopicIdPartition topicPartition = iterator.next();
newGroupAssignment.get(memberIndex).get(topicPartition.topicId()).remove(topicPartition.partitionId());
finalAssignmentByPartition.get(topicPartition).remove(memberIndex);
iterator.remove();
if (memberFinalAssignment.size() == memberDesiredAssignmentCount) {
break;
}
}
}
});
}

/**
* Revoke any over-shared partitions.
*/
private void revokeOversharedPartitions() {
finalAssignmentByPartition.forEach((topicPartition, assignedMembers) -> {
Expand All @@ -283,8 +308,13 @@ private void revokeOversharedPartitions() {
Iterator<Integer> assignedMemberIterator = assignedMembers.iterator();
while (assignedMemberIterator.hasNext()) {
Integer memberIndex = assignedMemberIterator.next();
if (overfilledMembers.contains(memberIndex)) {
Set<Integer> partitions = newGroupAssignment.get(memberIndex).get(topicPartition.topicId());
Map<Uuid, Set<Integer>> newMemberAssignment = newGroupAssignment.get(memberIndex);
if (newMemberAssignment == null) {
newMemberAssignment = AssignorHelpers.deepCopyAssignment(oldGroupAssignment.get(memberIndex));
newGroupAssignment.put(memberIndex, newMemberAssignment);
}
Set<Integer> partitions = newMemberAssignment.get(topicPartition.topicId());
if (partitions != null) {
if (partitions.remove(topicPartition.partitionId())) {
assignedMemberCount--;
assignedMemberIterator.remove();
Expand All @@ -297,55 +327,6 @@ private void revokeOversharedPartitions() {
}
}
}
if (assignedMemberCount > desiredSharing) {
Iterator<Integer> assignedMemberIterator = assignedMembers.iterator();
while (assignedMemberIterator.hasNext()) {
Integer memberIndex = assignedMemberIterator.next();
if (!overfilledMembers.contains(memberIndex)) {
Map<Uuid, Set<Integer>> newMemberAssignment = newGroupAssignment.get(memberIndex);
if (newMemberAssignment == null) {
newMemberAssignment = AssignorHelpers.deepCopyAssignment(oldGroupAssignment.get(memberIndex));
newGroupAssignment.put(memberIndex, newMemberAssignment);
}
Set<Integer> partitions = newMemberAssignment.get(topicPartition.topicId());
if (partitions != null) {
if (partitions.remove(topicPartition.partitionId())) {
assignedMemberCount--;
assignedMemberIterator.remove();
finalAssignmentByMember.get(memberIndex).remove(topicPartition);
unfilledMembers.add(memberIndex);
}
}
}
if (assignedMemberCount <= desiredSharing) {
break;
}
}
}
});
}

/**
* Revoke partitions from members which are still overfilled.
*/
private void revokeOverfilledMembers() {
if (overfilledMembers.isEmpty())
return;

overfilledMembers.forEach(memberIndex -> {
int memberDesiredAssignmentCount = desiredAssignmentCount[memberIndex];
Set<TopicIdPartition> memberFinalAssignment = finalAssignmentByMember.get(memberIndex);
if (memberFinalAssignment.size() > memberDesiredAssignmentCount) {
Iterator<TopicIdPartition> iterator = memberFinalAssignment.iterator();
while (iterator.hasNext()) {
TopicIdPartition topicPartition = iterator.next();
finalAssignmentByPartition.get(topicPartition).remove(memberIndex);
iterator.remove();
if (memberFinalAssignment.size() == memberDesiredAssignmentCount) {
break;
}
}
}
});
}

Expand Down