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Posted to jira@kafka.apache.org by GitBox <gi...@apache.org> on 2020/09/22 17:14:11 UTC
[GitHub] [kafka] abbccdda commented on a change in pull request #9270: [WIP] KAFKA-10284: Group membership update due to static member rejoin should be persisted
abbccdda commented on a change in pull request #9270:
URL: https://github.com/apache/kafka/pull/9270#discussion_r492896997
##########
File path: core/src/test/scala/unit/kafka/coordinator/group/GroupCoordinatorTest.scala
##########
@@ -3882,6 +3942,21 @@ class GroupCoordinatorTest {
Await.result(responseFuture, Duration(rebalanceTimeout + 100, TimeUnit.MILLISECONDS))
}
+ private def staticJoinGroupWithPersistence(groupId: String,
+ memberId: String,
Review comment:
nit: alignment
##########
File path: core/src/main/scala/kafka/coordinator/group/GroupCoordinator.scala
##########
@@ -1040,21 +1040,36 @@ class GroupCoordinator(val brokerId: Int,
group.currentState match {
case Stable =>
- info(s"Static member joins during Stable stage will not trigger rebalance.")
- group.maybeInvokeJoinCallback(member, JoinGroupResult(
- members = List.empty,
- memberId = newMemberId,
- generationId = group.generationId,
- protocolType = group.protocolType,
- protocolName = group.protocolName,
- // We want to avoid current leader performing trivial assignment while the group
- // is in stable stage, because the new assignment in leader's next sync call
- // won't be broadcast by a stable group. This could be guaranteed by
- // always returning the old leader id so that the current leader won't assume itself
- // as a leader based on the returned message, since the new member.id won't match
- // returned leader id, therefore no assignment will be performed.
- leaderId = currentLeader,
- error = Errors.NONE))
+ // check if group's selectedProtocol of next generation will change, if not, simply store group to persist the
+ // updated static member, if yes, rebalance should be triggered to let the group's assignment and selectProtocol consistent
+ val selectedProtocolOfNextGeneration = group.selectProtocol
+ if (group.protocolName.contains(selectedProtocolOfNextGeneration)) {
+ info(s"Static member which joins during Stable stage and doesn't affect selectProtocol will not trigger rebalance.")
+ val groupAssignment: Map[String, Array[Byte]] = group.allMemberMetadata.map(member => member.memberId -> member.assignment).toMap
+ groupManager.storeGroup(group, groupAssignment, error => {
+ group.inLock {
+ if (error != Errors.NONE) {
+ warn(s"Failed to persist metadata for group ${group.groupId}: ${error.message}")
+ }
+ }
+ })
+ group.maybeInvokeJoinCallback(member, JoinGroupResult(
+ members = List.empty,
+ memberId = newMemberId,
+ generationId = group.generationId,
+ protocolType = group.protocolType,
+ protocolName = group.protocolName,
+ // We want to avoid current leader performing trivial assignment while the group
+ // is in stable stage, because the new assignment in leader's next sync call
+ // won't be broadcast by a stable group. This could be guaranteed by
+ // always returning the old leader id so that the current leader won't assume itself
+ // as a leader based on the returned message, since the new member.id won't match
+ // returned leader id, therefore no assignment will be performed.
+ leaderId = currentLeader,
+ error = Errors.NONE))
+ } else {
+ maybePrepareRebalance(group, s"Group's selectedProtocol will change because static member ${member.memberId} with instance id $groupInstanceId joined with change of protocol")
Review comment:
Could you elaborate why this case is possible? We do have checks for `!group.supportsProtocols(protocolType, MemberMetadata.plainProtocolSet(protocols)` in the caller, so if the group protocol is incompatible, won't we just reject the rejoin?
##########
File path: core/src/main/scala/kafka/coordinator/group/GroupCoordinator.scala
##########
@@ -1040,21 +1040,36 @@ class GroupCoordinator(val brokerId: Int,
group.currentState match {
case Stable =>
- info(s"Static member joins during Stable stage will not trigger rebalance.")
- group.maybeInvokeJoinCallback(member, JoinGroupResult(
- members = List.empty,
- memberId = newMemberId,
- generationId = group.generationId,
- protocolType = group.protocolType,
- protocolName = group.protocolName,
- // We want to avoid current leader performing trivial assignment while the group
- // is in stable stage, because the new assignment in leader's next sync call
- // won't be broadcast by a stable group. This could be guaranteed by
- // always returning the old leader id so that the current leader won't assume itself
- // as a leader based on the returned message, since the new member.id won't match
- // returned leader id, therefore no assignment will be performed.
- leaderId = currentLeader,
- error = Errors.NONE))
+ // check if group's selectedProtocol of next generation will change, if not, simply store group to persist the
+ // updated static member, if yes, rebalance should be triggered to let the group's assignment and selectProtocol consistent
+ val selectedProtocolOfNextGeneration = group.selectProtocol
+ if (group.protocolName.contains(selectedProtocolOfNextGeneration)) {
+ info(s"Static member which joins during Stable stage and doesn't affect selectProtocol will not trigger rebalance.")
+ val groupAssignment: Map[String, Array[Byte]] = group.allMemberMetadata.map(member => member.memberId -> member.assignment).toMap
+ groupManager.storeGroup(group, groupAssignment, error => {
+ group.inLock {
+ if (error != Errors.NONE) {
Review comment:
Should we reply join failure if the persistence of the group metadata failed?
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