From c5fcb7f68bff055cc56e487bd48994945e7935cd Mon Sep 17 00:00:00 2001 From: jinxing Date: Wed, 1 Feb 2017 13:54:37 -0800 Subject: [SPARK-19347] ReceiverSupervisorImpl can add block to ReceiverTracker multiple times because of askWithRetry. ## What changes were proposed in this pull request? `ReceiverSupervisorImpl` on executor side reports block's meta back to `ReceiverTracker` on driver side. In current code, `askWithRetry` is used. However, for `AddBlock`, `ReceiverTracker` is not idempotent, which may result in messages are processed multiple times. **To reproduce**: 1. Check if it is the first time receiving `AddBlock` in `ReceiverTracker`, if so sleep long enough(say 200 seconds), thus the first RPC call will be timeout in `askWithRetry`, then `AddBlock` will be resent. 2. Rebuild Spark and run following job: ``` def streamProcessing(): Unit = { val conf = new SparkConf() .setAppName("StreamingTest") .setMaster(masterUrl) val ssc = new StreamingContext(conf, Seconds(200)) val stream = ssc.socketTextStream("localhost", 1234) stream.print() ssc.start() ssc.awaitTermination() } ``` **To fix**: It makes sense to provide a blocking version `ask` in RpcEndpointRef, as mentioned in SPARK-18113 (https://github.com/apache/spark/pull/16503#event-927953218). Because Netty RPC layer will not drop messages. `askWithRetry` is a leftover from akka days. It imposes restrictions on the caller(e.g. idempotency) and other things that people generally don't pay that much attention to when using it. ## How was this patch tested? Test manually. The scenario described above doesn't happen with this patch. Author: jinxing Closes #16690 from jinxing64/SPARK-19347. --- .../org/apache/spark/streaming/receiver/ReceiverSupervisorImpl.scala | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'streaming/src/main/scala') diff --git a/streaming/src/main/scala/org/apache/spark/streaming/receiver/ReceiverSupervisorImpl.scala b/streaming/src/main/scala/org/apache/spark/streaming/receiver/ReceiverSupervisorImpl.scala index eca7c79465..722024b8a6 100644 --- a/streaming/src/main/scala/org/apache/spark/streaming/receiver/ReceiverSupervisorImpl.scala +++ b/streaming/src/main/scala/org/apache/spark/streaming/receiver/ReceiverSupervisorImpl.scala @@ -159,7 +159,7 @@ private[streaming] class ReceiverSupervisorImpl( logDebug(s"Pushed block $blockId in ${(System.currentTimeMillis - time)} ms") val numRecords = blockStoreResult.numRecords val blockInfo = ReceivedBlockInfo(streamId, numRecords, metadataOption, blockStoreResult) - trackerEndpoint.askWithRetry[Boolean](AddBlock(blockInfo)) + trackerEndpoint.askSync[Boolean](AddBlock(blockInfo)) logDebug(s"Reported block $blockId") } -- cgit v1.2.3