[GitHub] flink pull request #5621: [FLINK-8517] fix missing synchronization in TaskEv...

[asfgit]

Github user asfgit closed the pull request at:

https://github.com/apache/flink/pull/5621


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[GitHub] flink pull request #5621: [FLINK-8517] fix missing synchronization in TaskEv...

[NicoK]

GitHub user NicoK opened a pull request:

https://github.com/apache/flink/pull/5621

[FLINK-8517] fix missing synchronization in TaskEventDispatcher

## What is the purpose of the change

The `TaskEventDispatcher` was missing synchronization accessing the 
`registeredHandlers` field for the new `subscribeToEvent()` and `publish()` 
methods. This was causing the 
`StaticlyNestedIterationsITCase.testJobWithoutObjectReuse()` test to 
sporadically fail (reproducible after running a couple of times).

Please merge into `master` and `release-1.5` after accepting.

## Brief change log

- add synchronization around `TaskEventDispatcher#subscribeToEvent()`'s 
access to `registeredHandlers`
- add synchronization around `TaskEventDispatcher#publish()`'s access to 
`registeredHandlers`

## Verifying this change

This change is already covered by existing tests (indirectly), such as 
`StaticlyNestedIterationsITCase.testJobWithoutObjectReuse()`. I ran it almost 
24000 times and could not reproduce it anymore with the change

## Does this pull request potentially affect one of the following parts:

  - Dependencies (does it add or upgrade a dependency): **no**
  - The public API, i.e., is any changed class annotated with 
`@Public(Evolving)`: **no**
  - The serializers: **no**
  - The runtime per-record code paths (performance sensitive): **no**
  - Anything that affects deployment or recovery: JobManager (and its 
components), Checkpointing, Yarn/Mesos, ZooKeeper: **no**
  - The S3 file system connector: **no**

## Documentation

  - Does this pull request introduce a new feature? **no**
  - If yes, how is the feature documented? **not applicable**


You can merge this pull request into a Git repository by running:

$ git pull https://github.com/NicoK/flink flink-8517

Alternatively you can review and apply these changes as the patch at:

https://github.com/apache/flink/pull/5621.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 #5621


commit aabeb89dd1259174c786f19b7e97c4c50038610f
Author: Nico Kruber 
Date:   2018-03-02T13:38:20Z

[FLINK-8517] fix missing synchronization in TaskEventDispatcher




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