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https://issues.apache.org/jira/browse/FLINK-3336?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15132905#comment-15132905
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ASF GitHub Bot commented on FLINK-3336:
---------------------------------------
Github user uce commented on a diff in the pull request:
https://github.com/apache/flink/pull/1589#discussion_r51929574
--- Diff:
flink-streaming-java/src/main/java/org/apache/flink/streaming/api/datastream/DataStream.java
---
@@ -443,6 +443,35 @@ public ExecutionConfig getExecutionConfig() {
}
/**
+ * Sets the partitioning of the {@link DataStream} so that the output
elements
+ * are distributed evenly to a subset of instances of the next
operation in a round-robin
+ * fashion.
+ *
+ * <p>The subset of downstream operations to which the upstream
operation sends
+ * elements depends on the degree of parallelism of both the upstream
and downstream operation.
+ * For example, if the upstream operation has parallelism 2 and the
downstream operation
+ * has parallelism 4, then one upstream operation would distribute
elements to two
+ * downstream operations while the other upstream operation would
distribute to the other
+ * two downstream operations. If, on the other hand, the downstream
operation has parallelism
+ * 2 while the upstream operation has parallelism 4 then two upstream
operations will
+ * distribute to one downstream operation while the other two upstream
operations will
+ * distribute to the other downstream operations.
+ *
+ * <p>In cases where the different parallelisms are not multiples of
each other one or several
+ * downstream operations will have a differing number of inputs from
upstream operations.
+ *
+ * <p>
--- End diff --
Fine with me :) We would have to make sure that the other docs also mention
that it only affects the next operation.
> Add Semi-Rebalance Data Shipping for DataStream
> -----------------------------------------------
>
> Key: FLINK-3336
> URL: https://issues.apache.org/jira/browse/FLINK-3336
> Project: Flink
> Issue Type: Improvement
> Components: Streaming
> Reporter: Aljoscha Krettek
> Assignee: Aljoscha Krettek
> Fix For: 1.0.0
>
>
> This feature has recently been requested on the ML:
> http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Distribution-of-sinks-among-the-nodes-td4640.html
> The new data shipping pattern would allow to rebalance data only to a subset
> of downstream operations.
> The subset of downstream operations to which the upstream operation would send
> elements depends on the degree of parallelism of both the upstream and
> downstream operation.
> For example, if the upstream operation has parallelism 2 and the downstream
> operation
> has parallelism 4, then one upstream operation would distribute elements to
> two
> downstream operations while the other upstream operation would distribute to
> the other
> two downstream operations. If, on the other hand, the downstream operation
> had parallelism
> 2 while the upstream operation has parallelism 4 then two upstream operations
> would
> distribute to one downstream operation while the other two upstream
> operations would
> distribute to the other downstream operations.
> In cases where the different parallelisms are not multiples of each other one
> or several
> downstream operations would have a differing number of inputs from upstream
> operations.
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