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Shixiong Zhu commented on SPARK-18838: -------------------------------------- [~sitalke...@gmail.com] Instead of your proposal, I prefer to make ExecutorAllocationManager not depend on the listener bus, which may drop critical events. > High latency of event processing for large jobs > ----------------------------------------------- > > Key: SPARK-18838 > URL: https://issues.apache.org/jira/browse/SPARK-18838 > Project: Spark > Issue Type: Improvement > Affects Versions: 2.0.0 > Reporter: Sital Kedia > > Currently we are observing the issue of very high event processing delay in > driver's `ListenerBus` for large jobs with many tasks. Many critical > component of the scheduler like `ExecutorAllocationManager`, > `HeartbeatReceiver` depend on the `ListenerBus` events and these delay is > causing job failure. For example, a significant delay in receiving the > `SparkListenerTaskStart` might cause `ExecutorAllocationManager` manager to > remove an executor which is not idle. The event processor in `ListenerBus` > is a single thread which loops through all the Listeners for each event and > processes each event synchronously > https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/scheduler/LiveListenerBus.scala#L94. > > The single threaded processor often becomes the bottleneck for large jobs. > In addition to that, if one of the Listener is very slow, all the listeners > will pay the price of delay incurred by the slow listener. > To solve the above problems, we plan to have a per listener single threaded > executor service and separate event queue. That way we are not bottlenecked > by the single threaded event processor and also critical listeners will not > be penalized by the slow listeners. The downside of this approach is separate > event queue per listener will increase the driver memory footprint. -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org