showuon commented on a change in pull request #10509:
URL: https://github.com/apache/kafka/pull/10509#discussion_r625597504
##########
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
+ // so keep "minQuota" of the owned partitions, and revoke the
rest of the partitions
+ List<TopicPartition> minQuotaPartitions =
ownedPartitions.subList(0, minQuota);
+ consumerAssignment.addAll(minQuotaPartitions);
+ assignedPartitions.addAll(minQuotaPartitions);
+ allRevokedPartitions.addAll(ownedPartitions.subList(minQuota,
ownedPartitions.size()));
}
}
+ List<TopicPartition> unassignedPartitions =
getUnassignedPartitions(totalPartitionsCount, partitionsPerTopic,
assignedPartitions);
+ assignedPartitions = null;
+
+ if (log.isDebugEnabled()) {
+ log.debug("After reassigning previously owned partitions, unfilled
members: {}, unassigned partitions: {}, " +
+ "current assignment: {}", unfilledMembers,
unassignedPartitions, assignment);
+ }
+
Collections.sort(unfilledMembers);
- Iterator<TopicPartition> unassignedPartitionsIter =
unassignedPartitions.iterator();
-
- // Fill remaining members up to minQuota
- while (!unfilledMembers.isEmpty() && !unassignedPartitions.isEmpty()) {
- Iterator<String> unfilledConsumerIter = unfilledMembers.iterator();
-
- while (unfilledConsumerIter.hasNext()) {
- String consumer = unfilledConsumerIter.next();
- List<TopicPartition> consumerAssignment =
assignment.get(consumer);
-
- if (unassignedPartitionsIter.hasNext()) {
- TopicPartition tp = unassignedPartitionsIter.next();
- consumerAssignment.add(tp);
- unassignedPartitionsIter.remove();
- // We already assigned all possible ownedPartitions, so we
know this must be newly to this consumer
- if (allRevokedPartitions.contains(tp))
- partitionsTransferringOwnership.put(tp, consumer);
- } else {
- break;
- }
- if (consumerAssignment.size() == minQuota) {
- minCapacityMembers.add(consumer);
- unfilledConsumerIter.remove();
+ Iterator<String> unfilledConsumerIter = unfilledMembers.iterator();
+ // Round-Robin filling remaining members up to the expected numbers of
maxQuota, otherwise, to minQuota
+ for (TopicPartition unassignedPartition : unassignedPartitions) {
+ if (!unfilledConsumerIter.hasNext()) {
+ if (unfilledMembers.isEmpty()) {
+ // Should not enter here since we have calculated the
exact number to assign to each consumer
+ log.warn("No more unfilled consumers to be assigned.");
Review comment:
Agree!
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