How can I deserialize JSON {name, value} in C#?

Hadoop: Running job with small subset runs fine, but fails on larger set of data?

I have a following situation I have 3 machines cluster with following confirguration. Master Usage of /: 91.4% of 74.41GB MemTotal: 16557308 kB MemFree: 723736 kB Slave 01 Usage of /: 52.9% of 29.76GB MemTotal: 16466220 kB MemFree: 5320860 kB Slave 02 Usage of /: 19.0% of 19.84GB MemTotal: 16466220 kB MemFree: 6173564 kB hadoop/conf/core-site.xml <?xml version="1.0"?> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>  <configuration> <property> <name>hadoop.tmp.dir</name> <value>/work/app/hadoop/tmp</value> <description>A base for other temporary directories.</description> </property> <property> <name>fs.default.name</name> <value>hdfs://master:54310</value> <description>The name of the default file system. A URI whose scheme and authority determine the FileSystem implementation. The uri's scheme determines the config property (fs.SCHEME.impl) naming the FileSystem implementation class. The uri's authority is used to determine the host, port, etc. for a filesystem.</description> </property> <property> <name>dfs.datanode.max.xcievers</name> <value>4096</value> </property> </configuration> hadoop/conf/mapred-site.xml <?xml version="1.0"?> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>  <configuration> <property> <name>mapred.job.tracker</name> <value>master:54311</value> <description>The host and port that the MapReduce job tracker runs at. If "local", then jobs are run in-process as a single map and reduce task. </description> </property> <property> <name>mapred.reduce.tasks</name> <value>1</value> </property> <property> <name>mapred.map.tasks</name> <value>100</value> </property> <property> <name>mapred.task.timeout</name> <value>0</value> </property> <property> <name>mapred.child.java.opts</name> <value>-Xmx512m</value> </property> </configuration> hadoop/conf/hdfs-site.xml <?xml version="1.0"?> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>  <configuration> <property> <name>dfs.replication</name> <value>3</value> <description>Default block replication. The actual number of replications can be specified when the file is created. The default is used if replication is not specified in create time. </description> </property> <property> <name>dfs.datanode.socket.write.timeout</name> <value>0</value> </property> </configuration> - I have over 2 million XML documents(each document size ~ 400 KB) - `map` tasks opens each of these xmls and emit them as `JSON` - `reduce` task gets each of these `JSON` as string, applies transformation and emits it - no. of `map` tasks - 100 - no. of `reduce` tasks - 01 - The entire job runs good when `number of documents = 10,000` - when `number of documents = 278262`, the job fails and I see various issues as following On WebUI on slave-01, slave-02 java.lang.Throwable: Child Error at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271) Caused by: java.io.IOException: Task process exit with nonzero status of 255. at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:258) On master java.lang.RuntimeException: java.io.IOException: Spill failed at org.apache.hadoop.streaming.PipeMapRed.waitOutputThreads(PipeMapRed.java:325) at org.apache.hadoop.streaming.PipeMapRed.mapRedFinished(PipeMapRed.java:545) at org.apache.hadoop.streaming.PipeMapper.close(PipeMapper.java:132) at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:57) at org.apache.hadoop.streaming.PipeMapRunner.run(PipeMapRunner.java:36) at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:436) at org.apache.hadoop.mapred.MapTask.run(MapTask.java:372) at org.apache.hadoop.mapred.Child$4.run(Child.java:261) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:396) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1059) at org.apache.hadoop.mapred.Child.main(Child.java:255) Caused by: java.io.IOException: Spill failed at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:1029) at org.apache.hadoop.mapred.MapTask$OldOutputCollector.collect(MapTask.java:592) at org.apache.hadoop.streaming.PipeMapRed$MROutputThread.run(PipeMapRed.java:381) Caused by: org.apache.hadoop.util.DiskChecker$DiskErrorException: Could not find any valid local directory for output/spill1.out at org.apache.hadoop.fs.LocalDirAllocator$AllocatorPerContext.getLocalPathForWrite(LocalDirAllocator.java:381) at org.apache.hadoop.fs.LocalDirAllocator.getLocalPathForWrite(LocalDirAllocator.java:146) at org.apache.hadoop.fs.LocalDirAllocator.getLocalPathForWrite(LocalDirAllocator.java:127) at org.apache.hadoop.mapred.MapOutputFile.getSpillFileForWrite(MapOutputFile.java:121) at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.sortAndSpill(MapTask.java:1392) at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.access$1800(MapTask.java:853) at org.apache.hadoop.mapred.MapTask$MapOutputBuffer$SpillThread.run(MapTask.java:1344) and java.lang.Throwable: Child Error at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271) Caused by: java.io.IOException: Creation of /work/app/hadoop/tmp/mapred/local/userlogs/job_201207220051_0001/attempt_201207220051_0001_m_000004_2 failed. at org.apache.hadoop.mapred.TaskLog.createTaskAttemptLogDir(TaskLog.java:102) at org.apache.hadoop.mapred.DefaultTaskController.createLogDir(DefaultTaskController.java:71) at org.apache.hadoop.mapred.TaskRunner.prepareLogFiles(TaskRunner.java:316) at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:228) ------- java.lang.Throwable: Child Error at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271) Caused by: java.io.IOException: Creation of /work/app/hadoop/tmp/mapred/local/userlogs/job_201207220051_0001/attempt_201207220051_0001_m_000004_2.cleanup failed. at org.apache.hadoop.mapred.TaskLog.createTaskAttemptLogDir(TaskLog.java:102) at org.apache.hadoop.mapred.DefaultTaskController.createLogDir(DefaultTaskController.java:71) at org.apache.hadoop.mapred.TaskRunner.prepareLogFiles(TaskRunner.java:316) at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:228) When I go and check logs in `slaves`, this is what I found in hadoop-hduser-datanode-hadoop-01.log 2012-07-22 09:26:52,795 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: Receiving block blk_-5384386931827098009_1010 src: /10.0.0.81:51402 dest: /10.0.0.82:50010 2012-07-22 09:26:52,800 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: IOException in BlockReceiver constructor. Cause is 2012-07-22 09:26:52,800 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: writeBlock blk_-5384386931827098009_1010 received exception java.io.IOException: Unexpected problem in creating temporary file for blk_-5384386931827098009_1010. File /work/app/hadoop/tmp/dfs/data/tmp/blk_-5384386931827098009 should not be present, but is. 2012-07-22 09:26:52,800 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: DatanodeRegistration(10.0.0.82:50010, storageID=DS-735951984-127.0.1.1-50010-1342943517618, infoPort=50075, ipcPort=50020):DataXceiver java.io.IOException: Unexpected problem in creating temporary file for blk_-5384386931827098009_1010. File /work/app/hadoop/tmp/dfs/data/tmp/blk_-5384386931827098009 should not be present, but is. at org.apache.hadoop.hdfs.server.datanode.FSDataset$FSVolume.createTmpFile(FSDataset.java:426) at org.apache.hadoop.hdfs.server.datanode.FSDataset$FSVolume.createTmpFile(FSDataset.java:404) at org.apache.hadoop.hdfs.server.datanode.FSDataset.createTmpFile(FSDataset.java:1249) at org.apache.hadoop.hdfs.server.datanode.FSDataset.writeToBlock(FSDataset.java:1138) at org.apache.hadoop.hdfs.server.datanode.BlockReceiver.<init>(BlockReceiver.java:99) at org.apache.hadoop.hdfs.server.datanode.DataXceiver.writeBlock(DataXceiver.java:299) at org.apache.hadoop.hdfs.server.datanode.DataXceiver.run(DataXceiver.java:107) at java.lang.Thread.run(Thread.java:662) Please help me understand what is that I need to do inorder to resolve this issue?
Answer:

Best place to get answer to such questions would be stackoverflow. Not to say that people at Quora won't be able to answer it. It's just that you would increase your chances of getting answer by posting it on Stackoverflow.

Vikalp Jain at Quora Visit the source

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