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https://issues.apache.org/jira/browse/TEZ-4193?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Gurleen S Dhody updated TEZ-4193:
---------------------------------
Summary: Async Dispatcher drained property (was: Async DIspatcher drained
property)
> Async Dispatcher drained property
> ---------------------------------
>
> Key: TEZ-4193
> URL: https://issues.apache.org/jira/browse/TEZ-4193
> Project: Apache Tez
> Issue Type: Bug
> Affects Versions: 0.9.1
> Reporter: Gurleen S Dhody
> Priority: Minor
> Labels: AsyncDispatcher, newbie, newbie++
> Fix For: 0.9.1
>
>
> [https://github.com/apache/tez/blob/cf111b1c896db94d40ea92fc6da2a6fcce356114/tez-common/src/main/java/org/apache/tez/common/AsyncDispatcher.java#L318]
> The drained property should be set after all dispatchers in the handle()
> [https://github.com/apache/tez/blob/cf111b1c896db94d40ea92fc6da2a6fcce356114/tez-common/src/main/java/org/apache/tez/common/AsyncDispatcher.java#L311]
> function are checked for.
> We should set
> {code:java}
> // drained = false;
> {code}
>
> [https://github.com/apache/tez/blob/cf111b1c896db94d40ea92fc6da2a6fcce356114/tez-common/src/main/java/org/apache/tez/common/AsyncDispatcher.java#L332
>
> |https://github.com/apache/tez/blob/cf111b1c896db94d40ea92fc6da2a6fcce356114/tez-common/src/main/java/org/apache/tez/common/AsyncDispatcher.java#L332]here.
> Reason is that the thread on the event queue might already be empty and
> waiting on
> [https://github.com/apache/tez/blob/cf111b1c896db94d40ea92fc6da2a6fcce356114/tez-common/src/main/java/org/apache/tez/common/AsyncDispatcher.java#L106
>
> |https://github.com/apache/tez/blob/cf111b1c896db94d40ea92fc6da2a6fcce356114/tez-common/src/main/java/org/apache/tez/common/AsyncDispatcher.java#L106]new
> event.
> Setting drained as false but passing the event to another dispatcher will
> cause issue when stopping this dispatcher service, when drainEventsOnStop is
> set true. The thread will be stuck in queue and drained property will be
> false causing a deadlock here
> [https://github.com/apache/tez/blob/cf111b1c896db94d40ea92fc6da2a6fcce356114/tez-common/src/main/java/org/apache/tez/common/AsyncDispatcher.java#L146]
> Needs to be addressed in
> [https://github.com/apache/tez/blob/cf111b1c896db94d40ea92fc6da2a6fcce356114/tez-common/src/main/java/org/apache/tez/common/AsyncDispatcherConcurrent.java]
> in AsyncConcurrecyDispatcher as well.
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