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ASF GitHub Bot commented on KAFKA-2811: --------------------------------------- GitHub user ymatsuda opened a pull request: https://github.com/apache/kafka/pull/526 KAFKA-2811: add standby tasks @guozhangwang * added a new config param "num.standby.replicas" (the default value is 0). * added a new abstract class AbstractTask * added StandbyTask as a subclass of AbstractTask * modified StreamTask to a subclass of AbstractTask * StreamThread * standby tasks are created by calling StreamThread.addStandbyTask() from onPartitionsAssigned() * standby tasks are destroyed by calling StreamThread.removeStandbyTasks() from onPartitionRevoked() * In addStandbyTasks(), change log partitions are assigned to restoreConsumer. * In removeStandByTasks(), change log partitions are removed from restoreConsumer. * StreamThread polls change log records using restoreConsumer in the runLoop with timeout=0. * If records are returned, StreamThread calls StandbyTask.update and pass records to each standby tasks. You can merge this pull request into a Git repository by running: $ git pull https://github.com/ymatsuda/kafka standby_task Alternatively you can review and apply these changes as the patch at: https://github.com/apache/kafka/pull/526.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 #526 ---- commit 4f015e107ede8b03cea9aeddd40c7f04bc930acc Author: Yasuhiro Matsuda <yasuh...@confluent.io> Date: 2015-11-13T18:51:20Z standby tasks commit ea8814e3d668da63847650718d107b9a1a47ceb9 Author: Yasuhiro Matsuda <yasuh...@confluent.io> Date: 2015-11-13T19:16:36Z cleanup ---- > Add standby tasks > ----------------- > > Key: KAFKA-2811 > URL: https://issues.apache.org/jira/browse/KAFKA-2811 > Project: Kafka > Issue Type: Sub-task > Components: kafka streams > Reporter: Yasuhiro Matsuda > Assignee: Yasuhiro Matsuda > > Restoring local state from state change-log topics can be expensive. To > alleviate this, we want to have an option to keep replications of local > states that are kept up to date. The task assignment logic should be aware of > existence of such replicas. -- This message was sent by Atlassian JIRA (v6.3.4#6332)