Documentation issue maybe

[Romain Gilles]

Hi all,

I think the code example in following section has a thread safety issue: https://ci.apache.org/projects/flink/flink-docs-release-1.9/dev/stream/testing.html#junit-rule-miniclusterwithclientresource

The class CollectSink is not thread safe as only the write to the values collection are synchronized but not the read: CollectSink.values.containsAll(...). Maybe if you use a CopyOnWriteArrayList instead of an ArrayList and remove the synchronized key work it should be ok.

Romain

[Zhenghua Gao]

Your are right that it's not thread-safety.

I think we can use Collections.synchronizedList() to get a thread-safety list[1].

And remove the synchronized keyword from the invoke interface.

I have created a ticket to track this[2], please feel free to fix it by make a pull request.

[1] https://docs.oracle.com/javase/7/docs/api/java/util/Collections.html#synchronizedList(java.util.List)

[2] https://issues.apache.org/jira/browse/FLINK-14650

On Thu, Nov 7, 2019 at 12:12 AM Romain Gilles <[hidden email]> wrote:

Hi all,

I think the code example in following section has a thread safety issue: https://ci.apache.org/projects/flink/flink-docs-release-1.9/dev/stream/testing.html#junit-rule-miniclusterwithclientresource

The class CollectSink is not thread safe as only the write to the values collection are synchronized but not the read: CollectSink.values.containsAll(...). Maybe if you use a CopyOnWriteArrayList instead of an ArrayList and remove the synchronized key work it should be ok.

Romain