我正在运行一个map reduce程序。然而，我得到了类似的输出，即使我运行它只有Map器或两者与Map器和减速机。
在这之后，它永远不会完成。它挂在那里。
我不明白为什么减速机是开始之前，Map已经完成100%？可能存在哪些潜在问题？
输出：

Map 10% Reduce 0%
Map 19% Reduce 0%
Map 21% Reduce 0%
Map 39% Reduce 0%
Map 49% Reduce 0%
Map 63% Reduce 0% 
Map 67% Reduce 0% 
Map 68% Reduce 0% 
Map 68% Reduce 22%
Map 69% Reduce 22%

以下是Map程序代码：

public class EntityCountMapper extends Mapper<LongWritable, Text, Text, IntWritable> {
  static String total_record="";

  @Override
  protected void map(LongWritable baseAddress, Text line, Context context)
        throws IOException, InterruptedException {

    Text entity=new Text();
    IntWritable one=new IntWritable(1);

    total_record=total_record.concat(line.toString());
    String[] fields=total_record.split("::");
    if(fields.length==24)
    {
        entity.set(fields[22].trim());          
        context.write(entity,one);
        total_record="";
    }       
  }
}