MaxCompute:Sleep example

Prerequisites

Complete the environment configuration for testing, see Getting started.

Preparations

1. Prepare the JAR package of the test program. In this topic, the JAR package is named mapreduce-examples.jar and stored in the bin\data\resources directory in the local installation path of MaxCompute.

2. Prepare test resources for SleepJob.

   -- When adding the JAR package for the first time, you can ignore the -f flag.
   add jar data\resources\mapreduce-examples.jar -f;

Procedure

jar -resources mapreduce-examples.jar -classpath data\resources\mapreduce-examples.jar 
com.aliyun.odps.mapred.open.example.Sleep 10;
jar -resources mapreduce-examples.jar -classpath data\resources\mapreduce-examples.jar 
com.aliyun.odps.mapred.open.example.Sleep 100;

Expected result

The job runs normally. The runtime of different sleep durations can be compared to determine the effect.

Sample code

For information about Project Object Model (POM) dependencies, see Precautions.

package com.aliyun.odps.mapred.open.example;
import java.io.IOException;
import com.aliyun.odps.mapred.JobClient;
import com.aliyun.odps.mapred.MapperBase;
import com.aliyun.odps.mapred.conf.JobConf;
public class Sleep {
  private static final String SLEEP_SECS = "sleep.secs";
  public static class MapperClass extends MapperBase {
    /** No data is entered, the map function is not executed, and the related logic can be written only into setup. */
    @Override
    public void setup(TaskContext context) throws IOException {
      try {
        /** Obtain the number of sleep seconds set in JobConf. */
        Thread.sleep(context.getJobConf().getInt(SLEEP_SECS, 1) * 1000);
      } catch (InterruptedException e) {
        throw new RuntimeException(e);
      }
    }
  }
  public static void main(String[] args) throws Exception {
    if (args.length != 1) {
      System.err.println("Usage: Sleep <sleep_secs>");
      System.exit(-1);
    }
    JobConf job = new JobConf();
    job.setMapperClass(MapperClass.class);
    /** This instance is also a MapOnly job and the number of reducers must be set to 0. */
    job.setNumReduceTasks(0);
    /** The number of mappers must be specified by the user because no input table is provided. */
    job.setNumMapTasks(1);
    job.set(SLEEP_SECS, args[0]);
    JobClient.runJob(job);
  }
}