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使用counter示例

更新时间:2017-06-07 13:26:11   分享:   

本示例中定义了三个Counter:map_outputs,reduce_outputs和global_counts。用户可以在Map/Reduce的setup, map/reduce及cleanup接口中获取任意自定义Counter,并进行操作。

测试准备

(1)准备好测试程序jar包,假设名字为mapreduce-examples.jar;

(2)准备好UserDefinedCounters测试表和资源;

  • 创建表

    create table wc_in (key string, value string);
    create table wc_out(key string, cnt bigint);
    
  • 添加资源

    add jar mapreduce-examples.jar -f;
    

(3)使用tunnel导入数据;

   tunnel upload data wc_in;
  • 导入wc_in表的数据文件data内容为:
    hello,odps

测试步骤

在odpscmd中执行UserDefinedCounters

jar -resources mapreduce-examples.jar -classpath mapreduce-examples.jar
    com.aliyun.odps.mapred.open.example.UserDefinedCounters wc_in wc_out

预期结果

作业成功结束,可以看到Counters的输出如下:

Counters: 3
com.aliyun.odps.mapred.open.example.UserDefinedCounters$MyCounter
MAP_TASKS=1
REDUCE_TASKS=1
TOTAL_TASKS=2

输出表wc_out中内容为:

+------------+------------+
| key        | cnt        |
+------------+------------+
| hello      | 1          |
| odps       | 1          |
+------------+------------+

代码示例

    package com.aliyun.odps.mapred.open.example;

    import java.io.IOException;
    import java.util.Iterator;

    import com.aliyun.odps.counter.Counter;
    import com.aliyun.odps.counter.Counters;
    import com.aliyun.odps.data.Record;
    import com.aliyun.odps.mapred.JobClient;
    import com.aliyun.odps.mapred.MapperBase;
    import com.aliyun.odps.mapred.ReducerBase;
    import com.aliyun.odps.mapred.RunningJob;
    import com.aliyun.odps.mapred.conf.JobConf;
    import com.aliyun.odps.mapred.utils.SchemaUtils;
    import com.aliyun.odps.mapred.utils.InputUtils;
    import com.aliyun.odps.mapred.utils.OutputUtils;
    import com.aliyun.odps.data.TableInfo;

    /**
     * 
     * User Defined Counters
     *
     **/
    public class UserDefinedCounters {

      enum MyCounter {
        TOTAL_TASKS, MAP_TASKS, REDUCE_TASKS
      }

      public static class TokenizerMapper extends MapperBase {
        private Record word;
        private Record one;

        @Override
        public void setup(TaskContext context) throws IOException {
          super.setup(context);
          Counter map_tasks = context.getCounter(MyCounter.MAP_TASKS);
          Counter total_tasks = context.getCounter(MyCounter.TOTAL_TASKS);
          map_tasks.increment(1);
          total_tasks.increment(1);

          word = context.createMapOutputKeyRecord();
          one = context.createMapOutputValueRecord();
          one.set(new Object[] { 1L });
        }

        @Override
        public void map(long recordNum, Record record, TaskContext context)
            throws IOException {
          for (int i = 0; i < record.getColumnCount(); i++) {
            word.set(new Object[] { record.get(i).toString() });
            context.write(word, one);
          }
        }
      }

      public static class SumReducer extends ReducerBase {
        private Record result = null;

        @Override
        public void setup(TaskContext context) throws IOException {
          result = context.createOutputRecord();
          Counter reduce_tasks = context.getCounter(MyCounter.REDUCE_TASKS);
          Counter total_tasks = context.getCounter(MyCounter.TOTAL_TASKS);
          reduce_tasks.increment(1);
          total_tasks.increment(1);
        }

        @Override
        public void reduce(Record key, Iterator<Record> values, TaskContext context)
            throws IOException {
          long count = 0;
          while (values.hasNext()) {
            Record val = values.next();
            count += (Long) val.get(0);
          }
          result.set(0, key.get(0));
          result.set(1, count);
          context.write(result);
        }
      }

      public static void main(String[] args) throws Exception {
        if (args.length != 2) {
          System.err
              .println("Usage: TestUserDefinedCounters <in_table> <out_table>");
          System.exit(2);
        }

        JobConf job = new JobConf();
        job.setMapperClass(TokenizerMapper.class);
        job.setReducerClass(SumReducer.class);

        job.setMapOutputKeySchema(SchemaUtils.fromString("word:string"));
        job.setMapOutputValueSchema(SchemaUtils.fromString("count:bigint"));

        InputUtils.addTable(TableInfo.builder().tableName(args[0]).build(), job);
        OutputUtils.addTable(TableInfo.builder().tableName(args[1]).build(), job);

        RunningJob rJob = JobClient.runJob(job);

        Counters counters = rJob.getCounters();
        long m = counters.findCounter(MyCounter.MAP_TASKS).getValue();
        long r = counters.findCounter(MyCounter.REDUCE_TASKS).getValue();
        long total = counters.findCounter(MyCounter.TOTAL_TASKS).getValue();

        System.exit(0);
      }
    }
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