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https://issues.apache.org/jira/browse/HDFS-11819?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16013362#comment-16013362
]
huaxiang sun commented on HDFS-11819:
-------------------------------------
Update after more log reading, so when the hedged read thread pool is
exhausted, the hedged read does not work anymore.
Since the thread is not interrupted, it is easy to exhaust the thread pool in
some error conditions.
https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java#L1228
Discussed with [~atm] and [~jzhuge], they will follow up with the new jira if
it can be improved after research. I am closing this one as invalid.
> HDFS client with hedged read, handle exceptions from callable when the
> hedged read thread pool is exhausted
> ------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-11819
> URL: https://issues.apache.org/jira/browse/HDFS-11819
> Project: Hadoop HDFS
> Issue Type: Bug
> Affects Versions: 3.0.0-alpha2
> Reporter: huaxiang sun
> Assignee: huaxiang sun
>
> When the hedged read thread pool is exhausted, the current behavior is that
> callable will be executed in the current thread context. The callable can
> throw out IOExceptions which is not handled and it will not start a 'hedged'
> read.
> https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java#L1131
> Please see the following exception:
> {code}
> 2017-05-11 22:42:35,883 WARN org.apache.hadoop.hdfs.BlockReaderFactory: I/O
> error constructing remote block reader.
> org.apache.hadoop.net.ConnectTimeoutException: 3000 millis timeout while
> waiting for channel to be ready for connect. ch :
> java.nio.channels.SocketChannel[connection-pending remote=/*.*.*.*:50010]
> at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:533)
> at
> org.apache.hadoop.hdfs.DFSClient.newConnectedPeer(DFSClient.java:3527)
> at
> org.apache.hadoop.hdfs.BlockReaderFactory.nextTcpPeer(BlockReaderFactory.java:840)
> at
> org.apache.hadoop.hdfs.BlockReaderFactory.getRemoteBlockReaderFromTcp(BlockReaderFactory.java:755)
> at
> org.apache.hadoop.hdfs.BlockReaderFactory.build(BlockReaderFactory.java:376)
> at
> org.apache.hadoop.hdfs.DFSInputStream.actualGetFromOneDataNode(DFSInputStream.java:1179)
> at
> org.apache.hadoop.hdfs.DFSInputStream.access$300(DFSInputStream.java:91)
> at
> org.apache.hadoop.hdfs.DFSInputStream$2.call(DFSInputStream.java:1141)
> at
> org.apache.hadoop.hdfs.DFSInputStream$2.call(DFSInputStream.java:1133)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at
> java.util.concurrent.ThreadPoolExecutor$CallerRunsPolicy.rejectedExecution(ThreadPoolExecutor.java:2022)
> at
> org.apache.hadoop.hdfs.DFSClient$2.rejectedExecution(DFSClient.java:3571)
> at
> java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:823)
> at
> java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1369)
> at
> java.util.concurrent.ExecutorCompletionService.submit(ExecutorCompletionService.java:181)
> at
> org.apache.hadoop.hdfs.DFSInputStream.hedgedFetchBlockByteRange(DFSInputStream.java:1280)
> at
> org.apache.hadoop.hdfs.DFSInputStream.pread(DFSInputStream.java:1477)
> at
> org.apache.hadoop.hdfs.DFSInputStream.read(DFSInputStream.java:1439)
> at
> org.apache.hadoop.fs.FSDataInputStream.read(FSDataInputStream.java:92)
> at
> org.apache.hadoop.hbase.io.FileLink$FileLinkInputStream.read(FileLink.java:167)
> at
> org.apache.hadoop.fs.FSDataInputStream.read(FSDataInputStream.java:92)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock.positionalReadWithExtra(HFileBlock.java:757)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock$AbstractFSReader.readAtOffset(HFileBlock.java:1457)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock$FSReaderImpl.readBlockDataInternal(HFileBlock.java:1682)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock$FSReaderImpl.readBlockData(HFileBlock.java:1542)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2.readBlock(HFileReaderV2.java:445)
> at
> org.apache.hadoop.hbase.util.CompoundBloomFilter.contains(CompoundBloomFilter.java:100)
> at
> org.apache.hadoop.hbase.regionserver.StoreFile$Reader.passesGeneralBloomFilter(StoreFile.java:1383)
> at
> org.apache.hadoop.hbase.regionserver.StoreFile$Reader.passesBloomFilter(StoreFile.java:1247)
> at
> org.apache.hadoop.hbase.regionserver.StoreFileScanner.shouldUseScanner(StoreFileScanner.java:469)
> at
> org.apache.hadoop.hbase.regionserver.StoreScanner.selectScannersFrom(StoreScanner.java:393)
> at
> org.apache.hadoop.hbase.regionserver.StoreScanner.getScannersNoCompaction(StoreScanner.java:312)
> at
> org.apache.hadoop.hbase.regionserver.StoreScanner.<init>(StoreScanner.java:192)
> at
> org.apache.hadoop.hbase.regionserver.HStore.createScanner(HStore.java:2106)
> at
> org.apache.hadoop.hbase.regionserver.HStore.getScanner(HStore.java:2096)
> at
> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.<init>(HRegion.java:5544)
> at
> org.apache.hadoop.hbase.regionserver.HRegion.instantiateRegionScanner(HRegion.java:2569)
> at
> org.apache.hadoop.hbase.regionserver.HRegion.getScanner(HRegion.java:2555)
> at
> org.apache.hadoop.hbase.regionserver.HRegion.getScanner(HRegion.java:2536)
> at org.apache.hadoop.hbase.regionserver.HRegion.get(HRegion.java:6791)
> at org.apache.hadoop.hbase.regionserver.HRegion.get(HRegion.java:6770)
> at
> org.apache.hadoop.hbase.regionserver.RSRpcServices.get(RSRpcServices.java:2025)
> at
> org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$2.callBlockingMethod(ClientProtos.java:33644)
> at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2170)
> at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:109)
> at
> org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:185)
> at
> org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:165)
> {code}
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