squah-confluent commented on code in PR #23688:
URL: https://github.com/apache/kafka/pull/23688#discussion_r4306322828
##########
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java:
##########
@@ -4365,46 +4431,86 @@ private UpdateTargetAssignmentResult<Assignment>
maybeUpdateTargetAssignment(
return
UpdateTargetAssignmentResult.fromLastTargetAssignment(group, updatedMember);
}
+ boolean offloadAssignor =
consumerGroupAssignorOffloadEnable(group.groupId());
+
String preferredServerAssignor = group.computePreferredServerAssignor(
member,
updatedMember
).orElse(defaultConsumerGroupAssignor.name());
- try {
- UpdatedMembersAndTargetAssignmentView<ConsumerGroupMember,
Assignment> updatedMembersAndTargetAssignment =
- new UpdatedMembersAndTargetAssignmentView<>(
- group.members(),
- group.staticMembers(),
- group.targetAssignment(),
- ConsumerGroupMember::instanceId
- );
-
updatedMembersAndTargetAssignment.addOrUpdateMember(updatedMember.memberId(),
updatedMember);
- long startTimeMs = time.milliseconds();
- GroupSpec groupSpec = new
GroupSpecBuilder.ConsumerGroupSpecBuilder()
- .withMembers(updatedMembersAndTargetAssignment.members())
- .withSubscriptionType(subscriptionType)
-
.withTargetAssignment(updatedMembersAndTargetAssignment.targetAssignment())
- .withInvertedTargetAssignment(group.invertedTargetAssignment())
- .withMetadataImage(metadataImage)
-
.withResolvedRegularExpressions(group.resolvedRegularExpressions())
- .build();
+ UpdatedMembersAndTargetAssignmentView<ConsumerGroupMember, Assignment>
updatedMembersAndTargetAssignment =
+ new UpdatedMembersAndTargetAssignmentView<>(
+ group.members(),
+ group.staticMembers(),
+ group.targetAssignment(),
+ ConsumerGroupMember::instanceId
+ );
+
updatedMembersAndTargetAssignment.addOrUpdateMember(updatedMember.memberId(),
updatedMember);
- TargetAssignmentBuilder assignmentResultBuilder =
+ // Use the same metadata image throughout.
+ CoordinatorMetadataImage metadataImage = this.metadataImage;
+
+ long groupSpecStartTimeMs = time.milliseconds();
+ GroupSpec groupSpec = new GroupSpecBuilder.ConsumerGroupSpecBuilder()
+ .withMembers(updatedMembersAndTargetAssignment.members())
+ .withSubscriptionType(subscriptionType)
+
.withTargetAssignment(updatedMembersAndTargetAssignment.targetAssignment())
+ .withInvertedTargetAssignment(group.invertedTargetAssignment())
+ .withMetadataImage(metadataImage)
+ .withResolvedRegularExpressions(group.resolvedRegularExpressions())
+ .withAssignorOffload(offloadAssignor)
+ .build();
+ long groupSpecTimeMs = time.milliseconds() - groupSpecStartTimeMs;
+
+ Supplier<TargetAssignmentBuilder.TargetAssignmentResult>
buildTargetAssignment = () -> {
+ long assignorStartTimeMs = time.milliseconds();
+ TargetAssignmentBuilder.TargetAssignmentResult assignmentResult =
new TargetAssignmentBuilder(groupEpoch,
consumerGroupAssignors.get(preferredServerAssignor))
.withTime(time)
.withMetadataImage(metadataImage)
- .withGroupSpec(groupSpec);
-
- TargetAssignmentBuilder.TargetAssignmentResult assignmentResult =
- assignmentResultBuilder.build();
- long assignorTimeMs = time.milliseconds() - startTimeMs;
+ .withGroupSpec(groupSpec)
+ .build();
+ long assignorTimeMs = time.milliseconds() - assignorStartTimeMs;
if (log.isDebugEnabled()) {
- log.debug("[GroupId {}] Computed a new target assignment for
epoch {} with '{}' assignor in {}ms: {}.",
- group.groupId(), groupEpoch, preferredServerAssignor,
assignorTimeMs, assignmentResult.targetAssignment());
+ log.debug("[GroupId {}] Computed a new target assignment for
epoch {} with '{}' assignor in {}ms after building the group spec in {}ms: {}.",
+ group.groupId(), groupEpoch, preferredServerAssignor,
assignorTimeMs, groupSpecTimeMs, assignmentResult.targetAssignment());
} else {
- log.info("[GroupId {}] Computed a new target assignment for
epoch {} with '{}' assignor in {}ms.",
- group.groupId(), groupEpoch, preferredServerAssignor,
assignorTimeMs);
+ log.info("[GroupId {}] Computed a new target assignment for
epoch {} with '{}' assignor in {}ms after building the group spec in {}ms.",
+ group.groupId(), groupEpoch, preferredServerAssignor,
assignorTimeMs, groupSpecTimeMs);
Review Comment:
> Does building the group spec take time? I wonder if the timing is useful
at all...
It does when offloading is enabled. Here are some timings that Claude
recorded with a homogeneous setup:
| Members | Spec build, offload off | Spec build, offload on | Assignment
build | Records build | Total, offload off | Total, offload on | Spec % of
total, offload off | Spec % of total, offload on |
|---|---|---|---|---|---|---|---|---|
| 100 | 0.002 | 0.058 | 0.075 | 0.022 | 0.107 | 0.153 | 1.9% | 37.9% |
| 500 | 0.018 | 0.285 | 0.194 | 0.023 | 0.238 | 0.468 | 7.6% | 60.9% |
| 1,000 | 0.026 | 0.495 | 0.311 | 0.030 | 0.461 | 0.916 | 5.6% | 54.0% |
| 5,000 | 0.122 | 2.539 | 1.513 | 0.106 | 1.685 | 4.404 | 7.2% | 57.7% |
| 10,000 | 0.279 | 5.186 | 3.140 | 0.202 | 3.754 | 8.547 | 7.4% | 60.7% |
Building the group spec takes half of the total assignment time.
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