Terasort 错误：请求的分区多于输入键 (1 > 0)

Question

我正在研究 Hadoop 基准测试，并使用 teragen 和 tera 排序工具来做同样的事情。

teragen 工具工作正常，为此我使用以下命令：

hadoop jar /Users/karan.verma/Documents/backups/h/hadoop-2.6.4/share/hadoop/mapreduce/hadoop-mapreduce-examples-*.jar  teragen -Dmapreduce.job.maps=100 1t random-data1

并在控制台上给出以下输出：

17/10/03 17:19:21 INFO mapreduce.Job: Job job_1507026170114_0005 completed successfully
17/10/03 17:19:21 INFO mapreduce.Job: Counters: 30
    File System Counters
        FILE: Number of bytes read=0
        FILE: Number of bytes written=10661490
        FILE: Number of read operations=0
        FILE: Number of large read operations=0
        FILE: Number of write operations=0
        HDFS: Number of bytes read=8594
        HDFS: Number of bytes written=0
        HDFS: Number of read operations=400
        HDFS: Number of large read operations=0
        HDFS: Number of write operations=200
    Job Counters 
        Launched map tasks=100
        Other local map tasks=100
        Total time spent by all maps in occupied slots (ms)=1089472
        Total time spent by all reduces in occupied slots (ms)=0
        Total time spent by all map tasks (ms)=1089472
        Total vcore-milliseconds taken by all map tasks=1089472
        Total megabyte-milliseconds taken by all map tasks=1115619328
    Map-Reduce Framework
        Map input records=0
        Map output records=0
        Input split bytes=8594
        Spilled Records=0
        Failed Shuffles=0
        Merged Map outputs=0
        GC time elapsed (ms)=9690
        CPU time spent (ms)=0
        Physical memory (bytes) snapshot=0
        Virtual memory (bytes) snapshot=0
        Total committed heap usage (bytes)=11115954176
    File Input Format Counters 
        Bytes Read=0
    File Output Format Counters 
        Bytes Written=0

当我使用以下命令执行 terasort 工具时，遵循这个：

hadoop jar  /Users/karan.verma/Documents/backups/h/hadoop-2.6.4/share/hadoop/mapreduce/hadoop-mapreduce-examples-*.jar  terasort random-data1 sorted-data

我收到以下错误：

17/10/03 17:20:10 INFO terasort.TeraSort: starting
17/10/03 17:20:10 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
17/10/03 17:20:11 INFO input.FileInputFormat: Total input paths to process : 100
Spent 168ms computing base-splits.
Spent 2ms computing TeraScheduler splits.
Computing input splits took 172ms
Sampling 10 splits of 100
Making 1 from 0 sampled records
17/10/03 17:20:11 ERROR terasort.TeraSort: Requested more partitions than input keys (1 > 0)

任何帮助，为什么会发生这种情况？配置部分有什么我遗漏的吗？

Answer 1

检查 teragen 命令的输出，因为生成的输出文件可能为空。如果输入数据大小为 0，则会出现此错误。