[
https://issues.apache.org/jira/browse/FLINK-5874?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15903628#comment-15903628
]
ASF GitHub Bot commented on FLINK-5874:
---------------------------------------
Github user zentol commented on a diff in the pull request:
https://github.com/apache/flink/pull/3501#discussion_r105239060
--- Diff:
flink-streaming-java/src/test/java/org/apache/flink/streaming/api/DataStreamTest.java
---
@@ -906,6 +919,256 @@ public void testChannelSelectors() {
}
/////////////////////////////////////////////////////////////
+ // KeyBy testing
+ /////////////////////////////////////////////////////////////
+
+ @Rule
+ public ExpectedException expectedException = ExpectedException.none();
--- End diff --
First time I'm seeing this pattern and i can't help but feel that a simple
try-catch block would be more readable.
> Reject arrays as keys in DataStream API to avoid inconsistent hashing
> ---------------------------------------------------------------------
>
> Key: FLINK-5874
> URL: https://issues.apache.org/jira/browse/FLINK-5874
> Project: Flink
> Issue Type: Bug
> Components: DataStream API
> Affects Versions: 1.2.0, 1.1.4
> Reporter: Robert Metzger
> Assignee: Kostas Kloudas
> Priority: Blocker
>
> This issue has been reported on the mailing list twice:
> -
> http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Previously-working-job-fails-on-Flink-1-2-0-td11741.html
> -
> http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Arrays-values-in-keyBy-td7530.html
> The problem is the following: We are using just Key[].hashCode() to compute
> the hash when shuffling data. Java's default hashCode() implementation
> doesn't take the arrays contents into account, but the memory address.
> This leads to different hash code on the sender and receiver side.
> In Flink 1.1 this means that the data is shuffled randomly and not keyed, and
> in Flink 1.2 the keygroups code detect a violation of the hashing.
> The proper fix of the problem would be to rely on Flink's {{TypeComparator}}
> class, which has a type-specific hashing function. But introducing this
> change would break compatibility with existing code.
> I'll file a JIRA for the 2.0 changes for that fix.
> For 1.2.1 and 1.3.0 we should at least reject arrays as keys.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
