Hi Jianshi, From my understanding, it may not be the problem of NIO or Netty, looking at your stack trace, the OOM is occurred in EAOM(ExternalAppendOnlyMap), theoretically EAOM can spill the data into disk if memory is not enough, but there might some issues when join key is skewed or key number is smaller, so you will meet OOM.
Maybe you could monitor each stage or task’s shuffle and GC status also system status to identify the problem. Thanks Jerry From: Jianshi Huang [mailto:jianshi.hu...@gmail.com] Sent: Thursday, March 5, 2015 2:32 PM To: Aaron Davidson Cc: user Subject: Re: Having lots of FetchFailedException in join One really interesting is that when I'm using the netty-based spark.shuffle.blockTransferService, there's no OOM error messages (java.lang.OutOfMemoryError: Java heap space). Any idea why it's not here? I'm using Spark 1.2.1. Jianshi On Thu, Mar 5, 2015 at 1:56 PM, Jianshi Huang <jianshi.hu...@gmail.com<mailto:jianshi.hu...@gmail.com>> wrote: I changed spark.shuffle.blockTransferService to nio and now I'm getting OOM errors, I'm doing a big join operation. 15/03/04 19:04:07 ERROR Executor: Exception in task 107.0 in stage 2.0 (TID 6207) java.lang.OutOfMemoryError: Java heap space at org.apache.spark.util.collection.CompactBuffer.growToSize(CompactBuffer.scala:142) at org.apache.spark.util.collection.CompactBuffer.$plus$eq(CompactBuffer.scala:74) at org.apache.spark.rdd.CoGroupedRDD$$anonfun$5.apply(CoGroupedRDD.scala:179) at org.apache.spark.rdd.CoGroupedRDD$$anonfun$5.apply(CoGroupedRDD.scala:178) at org.apache.spark.util.collection.ExternalAppendOnlyMap$$anonfun$2.apply(ExternalAppendOnlyMap.scala:122) at org.apache.spark.util.collection.ExternalAppendOnlyMap$$anonfun$2.apply(ExternalAppendOnlyMap.scala:121) at org.apache.spark.util.collection.AppendOnlyMap.changeValue(AppendOnlyMap.scala:138) at org.apache.spark.util.collection.SizeTrackingAppendOnlyMap.changeValue(SizeTrackingAppendOnlyMap.scala:32) at org.apache.spark.util.collection.ExternalAppendOnlyMap.insertAll(ExternalAppendOnlyMap.scala:130) at org.apache.spark.rdd.CoGroupedRDD$$anonfun$compute$5.apply(CoGroupedRDD.scala:160) at org.apache.spark.rdd.CoGroupedRDD$$anonfun$compute$5.apply(CoGroupedRDD.scala:159) at scala.collection.TraversableLike$WithFilter$$anonfun$foreach$1.apply(TraversableLike.scala:772) at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59) at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47) at scala.collection.TraversableLike$WithFilter.foreach(TraversableLike.scala:771) at org.apache.spark.rdd.CoGroupedRDD.compute(CoGroupedRDD.scala:159) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:280) at org.apache.spark.rdd.RDD.iterator(RDD.scala:247) at org.apache.spark.rdd.MappedValuesRDD.compute(MappedValuesRDD.scala:31) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:280) at org.apache.spark.rdd.RDD.iterator(RDD.scala:247) at org.apache.spark.rdd.FlatMappedValuesRDD.compute(FlatMappedValuesRDD.scala:31) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:280) at org.apache.spark.rdd.RDD.iterator(RDD.scala:247) at org.apache.spark.rdd.MappedRDD.compute(MappedRDD.scala:31) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:280) at org.apache.spark.rdd.RDD.iterator(RDD.scala:247) at org.apache.spark.rdd.MappedRDD.compute(MappedRDD.scala:31) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:280) at org.apache.spark.rdd.RDD.iterator(RDD.scala:247) at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:61) at org.apache.spark.scheduler.Task.run(Task.scala:56) Is join/cogroup still memory bound? Jianshi On Wed, Mar 4, 2015 at 2:11 PM, Jianshi Huang <jianshi.hu...@gmail.com<mailto:jianshi.hu...@gmail.com>> wrote: Hmm... ok, previous errors are still block fetch errors. 15/03/03 10:22:40 ERROR RetryingBlockFetcher: Exception while beginning fetch of 11 outstanding blocks java.io.IOException: Failed to connect to host-xxxx/xxxx:55597 at org.apache.spark.network.client.TransportClientFactory.createClient(TransportClientFactory.java:191) at org.apache.spark.network.client.TransportClientFactory.createClient(TransportClientFactory.java:156) at org.apache.spark.network.netty.NettyBlockTransferService$$anon$1.createAndStart(NettyBlockTransferService.scala:78) at org.apache.spark.network.shuffle.RetryingBlockFetcher.fetchAllOutstanding(RetryingBlockFetcher.java:140) at org.apache.spark.network.shuffle.RetryingBlockFetcher.start(RetryingBlockFetcher.java:120) at org.apache.spark.network.netty.NettyBlockTransferService.fetchBlocks(NettyBlockTransferService.scala:87) at org.apache.spark.storage.ShuffleBlockFetcherIterator.sendRequest(ShuffleBlockFetcherIterator.scala:149) at org.apache.spark.storage.ShuffleBlockFetcherIterator.next(ShuffleBlockFetcherIterator.scala:289) at org.apache.spark.storage.ShuffleBlockFetcherIterator.next(ShuffleBlockFetcherIterator.scala:53) at scala.collection.Iterator$$anon$13.hasNext(Iterator.scala:371) at org.apache.spark.util.CompletionIterator.hasNext(CompletionIterator.scala:32) at org.apache.spark.InterruptibleIterator.hasNext(InterruptibleIterator.scala:39) at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:327) at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:327) at org.apache.spark.util.collection.ExternalAppendOnlyMap.insertAll(ExternalAppendOnlyMap.scala:125) at org.apache.spark.rdd.CoGroupedRDD$$anonfun$compute$5.apply(CoGroupedRDD.scala:160) at org.apache.spark.rdd.CoGroupedRDD$$anonfun$compute$5.apply(CoGroupedRDD.scala:159) at scala.collection.TraversableLike$WithFilter$$anonfun$foreach$1.apply(TraversableLike.scala:772) at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59) at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47) at scala.collection.TraversableLike$WithFilter.foreach(TraversableLike.scala:771) at org.apache.spark.rdd.CoGroupedRDD.compute(CoGroupedRDD.scala:159) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:263) at org.apache.spark.rdd.RDD.iterator(RDD.scala:230) at org.apache.spark.rdd.MappedValuesRDD.compute(MappedValuesRDD.scala:31) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:263) at org.apache.spark.rdd.RDD.iterator(RDD.scala:230) at org.apache.spark.rdd.FlatMappedValuesRDD.compute(FlatMappedValuesRDD.scala:31) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:263) at org.apache.spark.rdd.RDD.iterator(RDD.scala:230) at org.apache.spark.rdd.MappedRDD.compute(MappedRDD.scala:31) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:263) at org.apache.spark.rdd.RDD.iterator(RDD.scala:230) at org.apache.spark.rdd.MappedRDD.compute(MappedRDD.scala:31) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:263) at org.apache.spark.rdd.RDD.iterator(RDD.scala:230) at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:61) at org.apache.spark.scheduler.Task.run(Task.scala:56) at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:197) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:724) Caused by: java.net.ConnectException: Connection refused: lvshdc5dn0518.lvs.paypal.com/10.196.244.48:55597<http://lvshdc5dn0518.lvs.paypal.com/10.196.244.48:55597> at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:735) at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:208) at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:287) at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:528) And I checked executor on container host-xxxx, everything is good. Jianshi On Wed, Mar 4, 2015 at 12:28 PM, Aaron Davidson <ilike...@gmail.com<mailto:ilike...@gmail.com>> wrote: Drat! That doesn't help. Could you scan from the top to see if there were any fatal errors preceding these? Sometimes a OOM will cause this type of issue further down. On Tue, Mar 3, 2015 at 8:16 PM, Jianshi Huang <jianshi.hu...@gmail.com<mailto:jianshi.hu...@gmail.com>> wrote: The failed executor has the following error messages. Any hints? 15/03/03 10:22:41 ERROR TransportRequestHandler: Error while invoking RpcHandler#receive() on RPC id 5711039715419258699 java.io.FileNotFoundException: /hadoop01/scratch/local/usercache/jianshuang/appcache/application_1421268539738_202330/spark-local-20150303100549-fc3b/02/shuffle_0_1458_0.index (No such file or directory) at java.io.FileInputStream.open(Native Method) at java.io.FileInputStream.<init>(FileInputStream.java:146) at org.apache.spark.shuffle.IndexShuffleBlockManager.getBlockData(IndexShuffleBlockManager.scala:109) at org.apache.spark.storage.BlockManager.getBlockData(BlockManager.scala:305) at org.apache.spark.network.netty.NettyBlockRpcServer$$anonfun$2.apply(NettyBlockRpcServer.scala:57) at org.apache.spark.network.netty.NettyBlockRpcServer$$anonfun$2.apply(NettyBlockRpcServer.scala:57) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33) at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:108) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.mutable.ArrayOps$ofRef.map(ArrayOps.scala:108) at org.apache.spark.network.netty.NettyBlockRpcServer.receive(NettyBlockRpcServer.scala:57) at org.apache.spark.network.server.TransportRequestHandler.processRpcRequest(TransportRequestHandler.java:124) at org.apache.spark.network.server.TransportRequestHandler.handle(TransportRequestHandler.java:97) at org.apache.spark.network.server.TransportChannelHandler.channelRead0(TransportChannelHandler.java:91) at org.apache.spark.network.server.TransportChannelHandler.channelRead0(TransportChannelHandler.java:44) at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:163) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:787) at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:130) at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:511) at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468) at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354) at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116) at java.lang.Thread.run(Thread.java:724) 15/03/03 10:22:41 ERROR TransportRequestHandler: Error while invoking RpcHandler#receive() on RPC id 7941985280808455530 java.io.FileNotFoundException: /hadoop01/scratch/local/usercache/jianshuang/appcache/application_1421268539738_202330/spark-local-20150303100549-fc3b/02/shuffle_0_1458_0.index (No such file or directory) at java.io.FileInputStream.open(Native Method) at java.io.FileInputStream.<init>(FileInputStream.java:146) at org.apache.spark.shuffle.IndexShuffleBlockManager.getBlockData(IndexShuffleBlockManager.scala:109) at org.apache.spark.storage.BlockManager.getBlockData(BlockManager.scala:305) at org.apache.spark.network.netty.NettyBlockRpcServer$$anonfun$2.apply(NettyBlockRpcServer.scala:57) at org.apache.spark.network.netty.NettyBlockRpcServer$$anonfun$2.apply(NettyBlockRpcServer.scala:57) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33) at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:108) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.mutable.ArrayOps$ofRef.map(ArrayOps.scala:108) at org.apache.spark.network.netty.NettyBlockRpcServer.receive(NettyBlockRpcServer.scala:57) at org.apache.spark.network.server.TransportRequestHandler.processRpcRequest(TransportRequestHandler.java:124) at org.apache.spark.network.server.TransportRequestHandler.handle(TransportRequestHandler.java:97) at org.apache.spark.network.server.TransportChannelHandler.channelRead0(TransportChannelHandler.java:91) at org.apache.spark.network.server.TransportChannelHandler.channelRead0(TransportChannelHandler.java:44) at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:163) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:787) at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:130) at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:511) at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468) at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354) at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116) at java.lang.Thread.run(Thread.java:724) 15/03/03 10:22:41 ERROR TransportRequestHandler: Error while invoking RpcHandler#receive() on RPC id 5413737659722448543 java.io.FileNotFoundException: /hadoop03/scratch/local/usercache/jianshuang/appcache/application_1421268539738_202330/spark-local-20150303100549-88ee/17/shuffle_0_1074_0.index (No such file or directory) at java.io.FileInputStream.open(Native Method) at java.io.FileInputStream.<init>(FileInputStream.java:146) at org.apache.spark.shuffle.IndexShuffleBlockManager.getBlockData(IndexShuffleBlockManager.scala:109) at org.apache.spark.storage.BlockManager.getBlockData(BlockManager.scala:305) at org.apache.spark.network.netty.NettyBlockRpcServer$$anonfun$2.apply(NettyBlockRpcServer.scala:57) at org.apache.spark.network.netty.NettyBlockRpcServer$$anonfun$2.apply(NettyBlockRpcServer.scala:57) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33) at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:108) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.mutable.ArrayOps$ofRef.map(ArrayOps.scala:108) at org.apache.spark.network.netty.NettyBlockRpcServer.receive(NettyBlockRpcServer.scala:57) at org.apache.spark.network.server.TransportRequestHandler.processRpcRequest(TransportRequestHandler.java:124) at org.apache.spark.network.server.TransportRequestHandler.handle(TransportRequestHandler.java:97) at org.apache.spark.network.server.TransportChannelHandler.channelRead0(TransportChannelHandler.java:91) at org.apache.spark.network.server.TransportChannelHandler.channelRead0(TransportChannelHandler.java:44) at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:163) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:787) at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:130) at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:511) at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468) at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354) at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116) at java.lang.Thread.run(Thread.java:724) Jianshi On Wed, Mar 4, 2015 at 3:25 AM, Aaron Davidson <ilike...@gmail.com<mailto:ilike...@gmail.com>> wrote: "Failed to connect" implies that the executor at that host died, please check its logs as well. On Tue, Mar 3, 2015 at 11:03 AM, Jianshi Huang <jianshi.hu...@gmail.com<mailto:jianshi.hu...@gmail.com>> wrote: Sorry that I forgot the subject. And in the driver, I got many FetchFailedException. The error messages are 15/03/03 10:34:32 WARN TaskSetManager: Lost task 31.0 in stage 2.2 (TID 7943, xxxx): FetchFailed(BlockManagerId(86, xxxx, 43070), shuffleId=0, mapId=24, reduceId=1220, message= org.apache.spark.shuffle.FetchFailedException: Failed to connect to xxxx/xxxx:43070 at org.apache.spark.shuffle.hash.BlockStoreShuffleFetcher$.org$apache$spark$shuffle$hash$BlockStoreShuffleFetcher$$unpackBlock$1(BlockStoreShuffleFetcher.scala:67) at org.apache.spark.shuffle.hash.BlockStoreShuffleFetcher$$anonfun$3.apply(BlockStoreShuffleFetcher.scala:83) at org.apache.spark.shuffle.hash.BlockStoreShuffleFetcher$$anonfun$3.apply(BlockStoreShuffleFetcher.scala:83) Jianshi On Wed, Mar 4, 2015 at 2:55 AM, Jianshi Huang <jianshi.hu...@gmail.com<mailto:jianshi.hu...@gmail.com>> wrote: Hi, I got this error message: 15/03/03 10:22:41 ERROR OneForOneBlockFetcher: Failed while starting block fetches java.lang.RuntimeException: java.io.FileNotFoundException: /hadoop01/scratch/local/usercache/jianshuang/appcache/application_1421268539738_202330/spark-local-20150303100549-fc3b/02/shuffle_0_1458_0.index (No such file or directory) at java.io.FileInputStream.open(Native Method) at java.io.FileInputStream.<init>(FileInputStream.java:146) at org.apache.spark.shuffle.IndexShuffleBlockManager.getBlockData(IndexShuffleBlockManager.scala:109) at org.apache.spark.storage.BlockManager.getBlockData(BlockManager.scala:305) at org.apache.spark.network.netty.NettyBlockRpcServer$$anonfun$2.apply(NettyBlockRpcServer.scala:57) at org.apache.spark.network.netty.NettyBlockRpcServer$$anonfun$2.apply(NettyBlockRpcServer.scala:57) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33) at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:108) at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) at scala.collection.mutable.ArrayOps$ofRef.map(ArrayOps.scala:108) at org.apache.spark.network.netty.NettyBlockRpcServer.receive(NettyBlockRpcServer.scala:57) And then for the same index file and executor, I got the following errors multiple times 15/03/03 10:22:41 ERROR ShuffleBlockFetcherIterator: Failed to get block(s) from host-xxxx:39534 java.lang.RuntimeException: java.io.FileNotFoundException: /hadoop01/scratch/local/usercache/jianshuang/appcache/application_1421268539738_202330/spark-local-20150303100549-fc3b/02/shuffle_0_1458_0.index (No such file or directory) 15/03/03 10:22:41 ERROR RetryingBlockFetcher: Failed to fetch block shuffle_0_13_1228, and will not retry (0 retries) java.lang.RuntimeException: java.io.FileNotFoundException: /hadoop01/scratch/local/usercache/jianshuang/appcache/application_1421268539738_202330/spark-local-20150303100549-fc3b/02/shuffle_0_1458_0.index (No such file or directory) ... Caused by: java.net.ConnectException: Connection refused: host-xxxx.... What's the problem? BTW, I'm using Spark 1.2.1-SNAPSHOT I built around Dec. 20. Is there any bug fixes related to shuffle block fetching or index files after that? Thanks, -- Jianshi Huang LinkedIn: jianshi Twitter: @jshuang Github & Blog: http://huangjs.github.com/ -- Jianshi Huang LinkedIn: jianshi Twitter: @jshuang Github & Blog: http://huangjs.github.com/ -- Jianshi Huang LinkedIn: jianshi Twitter: @jshuang Github & Blog: http://huangjs.github.com/ -- Jianshi Huang LinkedIn: jianshi Twitter: @jshuang Github & Blog: http://huangjs.github.com/ -- Jianshi Huang LinkedIn: jianshi Twitter: @jshuang Github & Blog: http://huangjs.github.com/ -- Jianshi Huang LinkedIn: jianshi Twitter: @jshuang Github & Blog: http://huangjs.github.com/