[jira] [Resolved] (SPARK-8367) ReliableKafka will loss data when `spark.streaming.blockInterval` was 0

["Sean Owen (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-8367?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sean Owen resolved SPARK-8367.
------------------------------
       Resolution: Fixed
    Fix Version/s: 1.5.0
                   1.4.1

> ReliableKafka will loss data when `spark.streaming.blockInterval` was 0
> -----------------------------------------------------------------------
>
>                 Key: SPARK-8367
>                 URL: https://issues.apache.org/jira/browse/SPARK-8367
>             Project: Spark
>          Issue Type: Bug
>          Components: Streaming
>    Affects Versions: 1.4.0
>            Reporter: SaintBacchus
>            Assignee: SaintBacchus
>             Fix For: 1.4.1, 1.5.0
>
>
> {code:title=BlockGenerator.scala|borderStyle=solid}
>   /** Change the buffer to which single records are added to. */
>   private def updateCurrentBuffer(time: Long): Unit = synchronized {
>     try {
>       val newBlockBuffer = currentBuffer
>       currentBuffer = new ArrayBuffer[Any]
>       if (newBlockBuffer.size > 0) {
>        val blockId = StreamBlockId(receiverId, time - blockIntervalMs)
>         val newBlock = new Block(blockId, newBlockBuffer)
>         listener.onGenerateBlock(blockId)
>         blocksForPushing.put(newBlock)  // put is blocking when queue is full
>         logDebug("Last element in " + blockId + " is " + newBlockBuffer.last)
>       }
>     } catch {
>       case ie: InterruptedException =>
>         logInfo("Block updating timer thread was interrupted")
>       case e: Exception =>
>         reportError("Error in block updating thread", e)
>     }
>   }
> {code}
> If *spark.streaming.blockInterval* was 0, the *blockId* in the code will always be the same because of  *time* was 0 and *blockIntervalMs* was 0 too.
> {code:title=ReliableKafkaReceiver.scala|borderStyle=solid}
>    private def rememberBlockOffsets(blockId: StreamBlockId): Unit = {
>     // Get a snapshot of current offset map and store with related block id.
>     val offsetSnapshot = topicPartitionOffsetMap.toMap
>     blockOffsetMap.put(blockId, offsetSnapshot)
>     topicPartitionOffsetMap.clear()
>   }
> {code}
> If the *blockId* was the same,  Streaming will commit the  *offset*  before the really data comsumed(data was waitting to be commit but the offset had updated and commit by previous commit)
> So when exception occures, the *offset* had commit but the data will loss since the data was in memory and not comsumed yet.



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