Hadoop - Is a gearbox waiting to enter Mapper?

as described in the header, when I execute my Hadoop program (and debug it in local mode), the following happens:

1. All 10 csv lines in my test data are processed correctly in Mapper, Partitioner and RawComperator (OutputKeyComparatorClass), which is called after the map step. But the OutputValueGroupingComparatorClass and ReduceClass functions DO NOT start after that.

2. My application is as follows. (due to space limitations, I omit the implementation of the classes that I use as configuration parameters if someone has an idea that includes them):

public class RetweetApplication {

    public static int DEBUG = 1;
    static String INPUT = "/home/ema/INPUT-H";
    static String OUTPUT = "/home/ema/OUTPUT-H "+ (new Date()).toString();

    public static void main(String[] args) {
    JobClient client = new JobClient();
    JobConf conf = new JobConf(RetweetApplication.class);


    if(DEBUG > 0){
        conf.set("mapred.job.tracker", "local");
        conf.set("fs.default.name", "file:///");
        conf.set("dfs.replication", "1");
    }


    FileInputFormat.setInputPaths(conf, new Path(INPUT));   
    FileOutputFormat.setOutputPath(conf, new Path(OUTPUT));


    //conf.setOutputKeyClass(Text.class);
    //conf.setOutputValueClass(Text.class);
    conf.setMapOutputKeyClass(Text.class);
    conf.setMapOutputValueClass(Text.class);

    conf.setMapperClass(RetweetMapper.class);
    conf.setPartitionerClass(TweetPartitioner.class);
    conf.setOutputKeyComparatorClass(TwitterValueGroupingComparator.class);
    conf.setOutputValueGroupingComparator(TwitterKeyGroupingComparator.class);
    conf.setReducerClass(RetweetReducer.class);

    conf.setOutputFormat(TextOutputFormat.class);

    client.setConf(conf);
    try {
        JobClient.runJob(conf);
    } catch (Exception e) {
        e.printStackTrace();
    }
    }
}

3. I get the following console output (sorry for the format, but somehow this log cannot be formatted correctly):

12/05/22 03:51:05 INFO mapred.MapTask: io.sort.mb = 100 12/05/22 03:51:05 INFO mapred.MapTask: = 79691776/99614720

12/05/22 03:51:05 INFO mapred.MapTask: = 262144/327680

12/05/22 03:51:06 INFO mapred.JobClient: map 0% 0%

12/05/22 03:51:11 INFO mapred.LocalJobRunner: :/home/ema/INPUT-H/: 0 + 967 12/05/22 03:51:12 INFO mapred.JobClient: map 39% 0%

12/05/22 03:51:14 INFO mapred.LocalJobRunner: file:/home/ema/INPUT-H/tweets: 0 + 967 12/05/22 03:51:15 INFO mapred.MapTask:

12/05/22 03:51:15 INFO mapred.MapTask: 0

12/05/22 03:51:15 INFO mapred.Task: : try_local_0001_m_000000_0 .

12/05/22 03:51:15 INFO mapred.JobClient: 79% 0%

12/05/22 03:51:17 INFO mapred.LocalJobRunner: :/home/ema/INPUT-H/: 0 + 967

12/05/22 03:51:17 INFO mapred.LocalJobRunner: :/home/ema/INPUT-H/: 0 + 967

12/05/22 03:51:17 INFO mapred.Task: '_local_0001_m_000000_0' .

12/05/22 03:51:17 INFO mapred.Task: ResourceCalculatorPlugin: org.apache.hadoop.util.LinuxResourceCalculatorPlugin@35eed0

12/05/22 03:51:17 INFO mapred.ReduceTask: ShuffleRamManager: MemoryLimit = 709551680, MaxSingleShuffleLimit = 177387920

12/05/22 03:51:17 INFO mapred.ReduceTask: try_local_0001_r_000000_0 :

12/05/22 03:51:17 INFO mapred.ReduceTask: try_local_0001_r_000000_0 :

12/05/22 03:51:17 INFO mapred.ReduceTask: try_local_0001_r_000000_0 :

12/05/22 03:51:17 INFO mapred.ReduceTask: _local_0001_r_000000_0 1 , 0 12/05/22 03:51:17 INFO mapred.ReduceTask: try_local_0001_r_000000_0 0 (0 0 dup hosts)

12/05/22 03:51:17 INFO mapred.ReduceTask: try_local_0001_r_000000_0 :

12/05/22 03:51:18 INFO mapred.JobClient: map 100% 0% 12/05/22 03:51:23 INFO mapred.LocalJobRunner: > >

.

4. , :

RetweetApplication (1) [Remote Java Application]    
    OpenJDK Client VM[localhost:5002]   
        Thread [main] (Running) 
        Thread [Thread-2] (Running) 
        Daemon Thread [communication thread] (Running)  
        Thread [MapOutputCopier attempt_local_0001_r_000000_0.0] (Running)  
        Thread [MapOutputCopier attempt_local_0001_r_000000_0.1] (Running)  
        Thread [MapOutputCopier attempt_local_0001_r_000000_0.2] (Running)  
        Thread [MapOutputCopier attempt_local_0001_r_000000_0.4] (Running)  
        Thread [MapOutputCopier attempt_local_0001_r_000000_0.3] (Running)  
        Daemon Thread [Thread for merging on-disk files] (Running)  
        Daemon Thread [Thread for merging in memory files] (Running)    
        Daemon Thread [Thread for polling Map Completion Events] (Running)  

- , Hadoop (. ), ? , , mapper/partitioner/etc.

UPDATE Chris (. ) , localMode, : isLocal ReduceTask ​​ false, true.

, , , , . : local , " " , , , local file:/// .

ReduceTask isLocal true, isLocal=true . , stacktrace:

12/05/22 14:28:28 INFO mapred.LocalJobRunner: 
12/05/22 14:28:28 INFO mapred.Merger: Merging 1 sorted segments
12/05/22 14:28:28 INFO mapred.Merger: Down to the last merge-pass, with 1 segments left of total size: 1956 bytes
12/05/22 14:28:28 INFO mapred.LocalJobRunner: 
12/05/22 14:28:29 WARN conf.Configuration: file:/tmp/hadoop-ema/mapred/local/localRunner/job_local_0001.xml:a attempt to override final parameter: fs.default.name;  Ignoring.
12/05/22 14:28:29 WARN conf.Configuration: file:/tmp/hadoop-ema/mapred/local/localRunner/job_local_0001.xml:a attempt to override final parameter: mapred.job.tracker;  Ignoring.
12/05/22 14:28:30 INFO ipc.Client: Retrying connect to server: master/127.0.0.1:9001. Already tried 0 time(s).
12/05/22 14:28:31 INFO ipc.Client: Retrying connect to server: master/127.0.0.1:9001. Already tried 1 time(s).
12/05/22 14:28:32 INFO ipc.Client: Retrying connect to server: master/127.0.0.1:9001. Already tried 2 time(s).
12/05/22 14:28:33 INFO ipc.Client: Retrying connect to server: master/127.0.0.1:9001. Already tried 3 time(s).
12/05/22 14:28:34 INFO ipc.Client: Retrying connect to server: master/127.0.0.1:9001. Already tried 4 time(s).
12/05/22 14:28:35 INFO ipc.Client: Retrying connect to server: master/127.0.0.1:9001. Already tried 5 time(s).
12/05/22 14:28:36 INFO ipc.Client: Retrying connect to server: master/127.0.0.1:9001. Already tried 6 time(s).
12/05/22 14:28:37 INFO ipc.Client: Retrying connect to server: master/127.0.0.1:9001. Already tried 7 time(s).
12/05/22 14:28:38 INFO ipc.Client: Retrying connect to server: master/127.0.0.1:9001. Already tried 8 time(s).
12/05/22 14:28:39 INFO ipc.Client: Retrying connect to server: master/127.0.0.1:9001. Already tried 9 time(s).
12/05/22 14:28:39 WARN conf.Configuration: file:/tmp/hadoop-ema/mapred/local/localRunner/job_local_0001.xml:a attempt to override final parameter: fs.default.name;  Ignoring.
12/05/22 14:28:39 WARN conf.Configuration: file:/tmp/hadoop-ema/mapred/local/localRunner/job_local_0001.xml:a attempt to override final parameter: mapred.job.tracker;  Ignoring.
12/05/22 14:28:39 WARN mapred.LocalJobRunner: job_local_0001
java.net.ConnectException: Call to master/127.0.0.1:9001 failed on connection exception: java.net.ConnectException: Connection refused
    at org.apache.hadoop.ipc.Client.wrapException(Client.java:1095)
    at org.apache.hadoop.ipc.Client.call(Client.java:1071)
    at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:225)
    at $Proxy1.getProtocolVersion(Unknown Source)
    at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:396)
    at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:379)
    at org.apache.hadoop.hdfs.DFSClient.createRPCNamenode(DFSClient.java:119)
    at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:238)
    at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:203)
    at org.apache.hadoop.hdfs.DistributedFileSystem.initialize(DistributedFileSystem.java:89)
    at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:1386)
    at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:66)
    at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:1404)
    at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:254)
    at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:123)
    at org.apache.hadoop.mapred.ReduceTask$OldTrackingRecordWriter.<init>(ReduceTask.java:446)
    at org.apache.hadoop.mapred.ReduceTask.runOldReducer(ReduceTask.java:490)
    at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:420)
    at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:260)
Caused by: java.net.ConnectException: Connection refused
    at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
    at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:592)
    at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
    at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:489)
    at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:434)
    at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:560)
    at org.apache.hadoop.ipc.Client$Connection.access$2000(Client.java:184)
    at org.apache.hadoop.ipc.Client.getConnection(Client.java:1202)
    at org.apache.hadoop.ipc.Client.call(Client.java:1046)
    ... 17 more
12/05/22 14:28:39 WARN conf.Configuration: file:/tmp/hadoop-ema/mapred/local/localRunner/job_local_0001.xml:a attempt to override final parameter: fs.default.name;  Ignoring.
12/05/22 14:28:39 WARN conf.Configuration: file:/tmp/hadoop-ema/mapred/local/localRunner/job_local_0001.xml:a attempt to override final parameter: mapred.job.tracker;  Ignoring.
12/05/22 14:28:39 INFO mapred.JobClient: Job complete: job_local_0001
12/05/22 14:28:39 INFO mapred.JobClient: Counters: 20
12/05/22 14:28:39 INFO mapred.JobClient:   File Input Format Counters 
12/05/22 14:28:39 INFO mapred.JobClient:     Bytes Read=967
12/05/22 14:28:39 INFO mapred.JobClient:   FileSystemCounters
12/05/22 14:28:39 INFO mapred.JobClient:     FILE_BYTES_READ=14093
12/05/22 14:28:39 INFO mapred.JobClient:     FILE_BYTES_WRITTEN=47859
12/05/22 14:28:39 INFO mapred.JobClient:   Map-Reduce Framework
12/05/22 14:28:39 INFO mapred.JobClient:     Map output materialized bytes=1960
12/05/22 14:28:39 INFO mapred.JobClient:     Map input records=10
12/05/22 14:28:39 INFO mapred.JobClient:     Reduce shuffle bytes=0
12/05/22 14:28:39 INFO mapred.JobClient:     Spilled Records=10
12/05/22 14:28:39 INFO mapred.JobClient:     Map output bytes=1934
12/05/22 14:28:39 INFO mapred.JobClient:     Total committed heap usage (bytes)=115937280
12/05/22 14:28:39 INFO mapred.JobClient:     CPU time spent (ms)=0
12/05/22 14:28:39 INFO mapred.JobClient:     Map input bytes=967
12/05/22 14:28:39 INFO mapred.JobClient:     SPLIT_RAW_BYTES=82
12/05/22 14:28:39 INFO mapred.JobClient:     Combine input records=0
12/05/22 14:28:39 INFO mapred.JobClient:     Reduce input records=0
12/05/22 14:28:39 INFO mapred.JobClient:     Reduce input groups=0
12/05/22 14:28:39 INFO mapred.JobClient:     Combine output records=0
12/05/22 14:28:39 INFO mapred.JobClient:     Physical memory (bytes) snapshot=0
12/05/22 14:28:39 INFO mapred.JobClient:     Reduce output records=0
12/05/22 14:28:39 INFO mapred.JobClient:     Virtual memory (bytes) snapshot=0
12/05/22 14:28:39 INFO mapred.JobClient:     Map output records=10
12/05/22 14:28:39 INFO mapred.JobClient: Job Failed: NA
java.io.IOException: Job failed!
    at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:1265)
    at uni.kassel.macek.rtprep.RetweetApplication.main(RetweetApplication.java:50)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:156)

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RESUME: : XML ( ) JAVA. - , , , , !;)

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+3
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, , , final conf xml , :

12/05/22 14:28:29 WARN conf.Configuration: file:/tmp/hadoop-ema/mapred/local/localRunner/job_local_0001.xml:a attempt to override final parameter: fs.default.name;  Ignoring.
12/05/22 14:28:29 WARN conf.Configuration: file:/tmp/hadoop-ema/mapred/local/localRunner/job_local_0001.xml:a attempt to override final parameter: mapred.job.tracker;  Ignoring.

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, conf - hasoop , "final"

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