GitHub user onurkaraman opened a pull request:
https://github.com/apache/kafka/pull/3765
KAFKA-5642 [WIP]: Use async ZookeeperClient in Controller
Synchronous zookeeper writes means that we wait an entire round trip before
doing the next write. These synchronous writes are happening at a per-partition
granularity in several places, so partition-heavy clusters suffer from the
controller doing many sequential round trips to zookeeper:
- PartitionStateMachine.electLeaderForPartition updates leaderAndIsr in
zookeeper on transition to OnlinePartition. This gets triggered per-partition
sequentially with synchronous writes during controlled shutdown of the shutting
down broker's replicas for which it is the leader.
- ReplicaStateMachine updates leaderAndIsr in zookeeper on transition to
OfflineReplica when calling KafkaController.removeReplicaFromIsr. This gets
triggered per-partition sequentially with synchronous writes for failed or
controlled shutdown brokers.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/onurkaraman/kafka KAFKA-5642
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/kafka/pull/3765.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #3765
----
commit 4b3e4e8b1d403bf817aeaa9196fb69a15b1a13a0
Author: Onur Karaman <okara...@linkedin.com>
Date: 2017-07-27T18:29:35Z
KAFKA-5642: Use async ZookeeperClient in Controller
Synchronous zookeeper writes means that we wait an entire round trip before
doing the next write. These synchronous writes are happening at a per-partition
granularity in several places, so partition-heavy clusters suffer from the
controller doing many sequential round trips to zookeeper:
- PartitionStateMachine.electLeaderForPartition updates leaderAndIsr in
zookeeper on transition to OnlinePartition. This gets triggered per-partition
sequentially with synchronous writes during controlled shutdown of the shutting
down broker's replicas for which it is the leader.
- ReplicaStateMachine updates leaderAndIsr in zookeeper on transition to
OfflineReplica when calling KafkaController.removeReplicaFromIsr. This gets
triggered per-partition sequentially with synchronous writes for failed or
controlled shutdown brokers.
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