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https://issues.apache.org/jira/browse/SPARK-4174?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sean Owen updated SPARK-4174:
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    Component/s: Streaming

> Streaming: Optionally provide notifications to Receivers when DStream has 
> been generated
> ----------------------------------------------------------------------------------------
>
>                 Key: SPARK-4174
>                 URL: https://issues.apache.org/jira/browse/SPARK-4174
>             Project: Spark
>          Issue Type: Improvement
>          Components: Streaming
>            Reporter: Hari Shreedharan
>            Assignee: Hari Shreedharan
>
> Receivers receiving data from Message Queues, like Active MQ, Kafka etc can 
> replay messages if required. Using the HDFS WAL mechanism for such systems 
> affects efficiency as we are incurring an unnecessary HDFS write when we can 
> recover the data from the queue anyway.
> We can fix this by providing a notification to the receiver when the RDD is 
> generated from the blocks. We need to consider the case where a receiver 
> might fail before the RDD is generated and come back on a different executor 
> when the RDD is generated. Either way, this is likely to cause duplicates and 
> not data loss -- so we may be ok.
> I am thinking about something of the order of accepting a callback function 
> which gets called when the RDD is generated. We can keep the function local 
> in a map of batch id -> function, which gets called when the function gets 
> generated (we can inform the ReceiverSupervisorImpl via Akka when the driver 
> generates the RDD). Of course, just an early thought - I will work on a 
> design doc for this one.



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