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https://issues.apache.org/jira/browse/FLINK-2620?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Flink Jira Bot updated FLINK-2620:
----------------------------------
Labels: auto-deprioritized-major stale-minor (was:
auto-deprioritized-major)
I am the [Flink Jira Bot|https://github.com/apache/flink-jira-bot/] and I help
the community manage its development. I see this issues has been marked as
Minor but is unassigned and neither itself nor its Sub-Tasks have been updated
for 180 days. I have gone ahead and marked it "stale-minor". If this ticket is
still Minor, please either assign yourself or give an update. Afterwards,
please remove the label or in 7 days the issue will be deprioritized.
> StreamPartitioner is not properly initialized for shuffle and rebalance
> -----------------------------------------------------------------------
>
> Key: FLINK-2620
> URL: https://issues.apache.org/jira/browse/FLINK-2620
> Project: Flink
> Issue Type: Bug
> Components: API / DataStream
> Reporter: Matthias J. Sax
> Priority: Minor
> Labels: auto-deprioritized-major, stale-minor
>
> Using rebalance connection pattern, the round-robin distribution starts with
> the same receiver index in all parallel tasks. For high receiver dop and
> (very) small data, it might result in an inbalanced distribution. For
> example, 100 source tasks, each emitting 10 record to 100 consumer tasks.
> Thus, only the first 10 consumer tasks receive data (10 records each) while
> the other 90 do not.
> A possible fix would be, to compute different starting indexes for different
> producer tasks like
> {noformat}
> startIdx = (numReceivers / numSenders) * myIdx
> {noformat}
> For shuffle grouping, the random data generator is initialized with a unique
> seed for all parallel tasks. This should be changed such that each task uses
> a different seed.
> To achieve both, the StreamPartitioner class should be extended with a
> configuration / initialize method which is called on each parallel operator.
> For a full discussion please see the mailing list archive:
> https://mail-archives.apache.org/mod_mbox/flink-dev/201509.mbox/browser
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